Posted: 1/29/2006 2:42:10 PM EDT
I just do not understand what the hell this question is asking! Check this out:
"For f(x) = x3 + 2x2 – 5x + 8, find f(1)." Does that mean substitute negative 1 for the x variable? If so, WTF do I do with 2x2? 2[1(2)]? Is this asking for a solution, a simplification? Somebody smarter than me (like that's a task) tell me what the hell this gibbberish means? 

Well the day's just not complete without seeing some guy get cornholed by a kangaroo while wearing a cream pie on his head... Aimless
Tai Gan Jo Ju You wouldn't want to ban guns if one ever saved your daughter's life. 
14
I read it as: 3x + (2*2)5x +8 Ooh! ooh! I didn't even think of exponents.... 


Are the numbers after the x exponents? If so, the answer is 14, but not computed as posted above.
(1)(1)(1) + 2(1)(1) 5(1) + 8 = 1 + 2 +5 +8 = 14 


87.


"You can tell a lot about a fellow's character by his way of eating jellybeans."

I think the exponents got screwed up. It looks like the equation should read: f(x) = x^3 + 2x^2  5x + 8 In which case, f(1) = 1 + 2 + 5 + 8 = 14. Edited because I can't add. 


Exactly f(1) = 1*3 + 2*2  5*1 + 8 I forget the acronym for math operations order in an equation, but multiplication is before addition and subtraction. 


You may want to check your addition ABP. Unless CA is teaching that 151 = 16. Maybe that's how Arnold will balance the budget. 


The equation reads:
'a function of x is equal to {(x to the third power) + (2 times x squared) minus (5x) plus 8} . Evaluate the equation for a value of f at 1. Not very difficult to solve. Charles. 

Semper Fidelis

PEMDAS Parentheses Exponents Multiplication Division Addition Subtraction 


I know the order of operations. I posted it EXACTLY as the question was written. I didn't change a thing, which is why I got so confused.


Well the day's just not complete without seeing some guy get cornholed by a kangaroo while wearing a cream pie on his head... Aimless
Tai Gan Jo Ju You wouldn't want to ban guns if one ever saved your daughter's life. 
Huh? Edit: is (f) equal to (1) or is (x)? There are no exponents in the problem, at least not how we usually do them like: 5^3 (five to the power of three). 

Well the day's just not complete without seeing some guy get cornholed by a kangaroo while wearing a cream pie on his head... Aimless
Tai Gan Jo Ju You wouldn't want to ban guns if one ever saved your daughter's life. 
C'Mon y'all, explain this to me in stupid talk.


Well the day's just not complete without seeing some guy get cornholed by a kangaroo while wearing a cream pie on his head... Aimless
Tai Gan Jo Ju You wouldn't want to ban guns if one ever saved your daughter's life. 
from my experience, that equation is way too conicidental to not be exponents. 


f(x) = x^3 + 2x^2  5x + 8 = (x*x*x) + (2*x*x)  (5*x) + 8 so f(1) = (1 * 1 * 1) + (2 * 1 * 1)  (5 * 1) + 8 = 1 + 2 + 5 + 8 = 14 


If that equation is indeed a precise rendition, then just substitute 1 for x at each location in the equation  f(x) = f(x= 1) = f(1) = (1)3 + 2(1)2  5(1) + 8 = 3 4 +5 +8 = 6 Actually, that is a good way to express that equation when testing student's knowledge about manipulating basic operations, but it is also a nonstandard way of organizing the terms. 

SYSTEM MESSAGE: tard limit exceeded on both sides.

Supreme Commander of the Forces of the Underworld
NJ, USA

X = 1 Substitute 1 for all of the Xs. f(1) = 3 + 2(1)2 + 5 + 8 7 + 5 + 8 2 + 8 f(1)= 6 f = 6 ? 

"When death smiles at you, all you can do is smile back."  Maximus

1911. I've heard rumors there are other handguns
FL, USA

the formula 'translation' and the answer is correct 

Romans 16:20
The God of peace will soon crush Satan under your feet. The grace of our Lord Jesus be with you. .......... nice <img src=/images/smilies/smiley_smartass.gif border=0 align=middle> 


SYSTEM MESSAGE: tard limit exceeded on both sides.

Don't you have a calculator?
Just press Y= and type in the equation man. 


1911. I've heard rumors there are other handguns
FL, USA

its just weird that it shows x3 instead of 3x, which is why I also believe its trying to say x^3 

Romans 16:20
The God of peace will soon crush Satan under your feet. The grace of our Lord Jesus be with you. .......... nice <img src=/images/smilies/smiley_smartass.gif border=0 align=middle> 
I have a TI BA II Plus, and it has no such button. Besides though, I don't want the calc to do the work. I want to know it  tht's the idea of college: to learn and then pass, not just to pass and walk away without retaining anything. If I can use the calc to check my answers, that would be great! But alas, I don't know what the "Y=" function does, nor does it appear I have one sigh. 

Well the day's just not complete without seeing some guy get cornholed by a kangaroo while wearing a cream pie on his head... Aimless
Tai Gan Jo Ju You wouldn't want to ban guns if one ever saved your daughter's life. 
Does it make sense any other way? We use ^ to denote exponents, so X to the third power is SUPPOSED to be written as X^3. That's where I am getting confused. Two variables (xy) mean "x times y" but when we use numers it means "real number times variable." So, 2x2 COULD mean "two to the power of two times two," "two times X to the power of two," or "two times X times two." With the (1) representing X it doesn't matter. But what is f(3)? The the way the problem is solved would mean everything, and I just want to know if anyone has had a problem similar to this that could possibly tell me how I am to decipher a real number with a variable with a real number grouped together. 2(3^2) is different than {2[3(2)]} and so is 2[3(2)]^2. See why I am confused? 1 won't change the solution, but if "f(3) = f(x)" then we have a problem with 2x2. I'm not wanting an answer per se, I am wanting to know what in algebra dictates the way we approach such a thing so that I know in the future. I really do appreciate everyone's help! Just trying to sort it all out. 

Well the day's just not complete without seeing some guy get cornholed by a kangaroo while wearing a cream pie on his head... Aimless
Tai Gan Jo Ju You wouldn't want to ban guns if one ever saved your daughter's life. 
To me the next logical question is "Why are you trying to solve this equation?" Are you doing it for a class you are taking? If so what types of things have you been talking about in class? What is the section of the book titled? All that info would help to decipher what the objective of the equation is.



The answer is 6. I think the problem is trying to confuse you by placing variables and coefficients in unconventional order. If you used the "^" for exponents in other problems to represent exponents, then I would not interpret this equation to have any exponents.



Yes, it is a question in college for "intermediate algebra." This is week 1. So far, we have discussed silly shit: order of operations, distribution property, terminology, etc. "The value of..." and stuff like that. So I went through the entire text and there is NO example of a question worded like this. Currently, we are discussing chapter 1, which is an overview of algebraic expressions, equations, and principles. Unfortunately for me, I quit school in 7th grade. I have NO math background except what I learned on my own and verified by getting my GED in '89 to go into the Army. What is a review for some is new to me, and this question makes no sense. So, the "quiz" for this week contained this question, exactly. And, as usual, I am lost. 

Well the day's just not complete without seeing some guy get cornholed by a kangaroo while wearing a cream pie on his head... Aimless
Tai Gan Jo Ju You wouldn't want to ban guns if one ever saved your daughter's life. 
At face value I would have to say this is an order of operations problem designed to test you on basic logic. If there are no exponents in the problem, as you have it written, then it is a simple matter of inserting (1) everywhere you see X and then solving the equation according to the proper order of operations.



richard
Take a look at the algebraic functions on this web page  campus.northpark.edu/math/PreCalculus/Algebraic/ This is the conventional method for displaying a value raised to a power. The use of the X^n format came about to accomodate computer programming and it has worked its way into everyday use, such as on pages like this where the word processor does not include a means to show the function as everyone expects it to look in a textbook. If you are copying this from a book or an instructor's typed notes, there is a fair chance the formatting was lost, hence the equation is not printed as it was originally intended. On the other hand, as I posted above, the way you wrote the function is a great way to test a students understanding. You need to check with the instructor to determine whether you are looking at a typo. Good luck in your classes. 

SYSTEM MESSAGE: tard limit exceeded on both sides.

I believe what you are seeing is a typo. An exponent can be expressed as 2x^2 or with a superscripted 2 behind the x. I suspect it is supposed to be superscripted and the formatting was lost somewhere. It is not standard practice to have a term like 2x2 (it would be represented by 4x if it were true). So, my guess is that the correct version is that it is 2 times xsquared or 2 times 1 times 1 = 2.
If you use f(3) then the answer (assuming the incorrect formatting described above) would be: 27 + 18 + 15 + 8 = 14 f(x) just means you are performing a function on the variable x. Whatever number is in the parentheses gets substituted for x. 


Best bet, ask the instructor for the correct format.



f(X)= is just another way of writing y=. The f(#) is just telling you what number to substitute for X.
The numbers after the X are understood to be the exponent you are raising the X to. Keep in mind that textbooks, especially math textbooks tend to have mistakes. Half the answers in the back of my calculus textbook are wrong, for example. 


Thank you, folks! Yes, I mailed the professor, but I haven't heard anything yet so I thought to ask y'all.


Well the day's just not complete without seeing some guy get cornholed by a kangaroo while wearing a cream pie on his head... Aimless
Tai Gan Jo Ju You wouldn't want to ban guns if one ever saved your daughter's life. 
1911. I've heard rumors there are other handguns
FL, USA

He's going to tell you the answer is '87' so get ready . eta: It'll turn out that he is an Arfcommer and has been secretly reading this thread . 

Romans 16:20
The God of peace will soon crush Satan under your feet. The grace of our Lord Jesus be with you. .......... nice <img src=/images/smilies/smiley_smartass.gif border=0 align=middle> 
You need a graphing calculator for the kind of class you're taking. Being able to see the answers graphically makes this type of math so much easier, trust me. I thought $125 calculator was a bunch of crap until I stated using it. I just got finished with my math homework and it's a piece of cake when you can use the calculator to do some of the work. Trust me, there is no learning value lost in the use of a calculator. When I was in high school, we never used a graphing calculator. What a mistake that was! In college, it's not only EXPECTED that you know how to use this thing, it makes it so much easier! I thought I was going to struggle in math forever, but this thing is truely a gift from god. Once you learn how to use it, a graphing calculator is the shit. Mine is a TI84 Plus Silver Edition, but there are others that do similar functions. As long as it can graph and table equations at my level of math, it's enough for me. YMMV. 


Tag for the reply from the professor.


"Don't go by the book! Think like a pirate!"

The...answer...to...the...question...is...fourtytwo.
Sorry, couldn't resist. Hope the professor squares you away. 


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