Warning

 

Close

Confirm Action

Are you sure you wish to do this?

Confirm Cancel
Member Login
Site Notices
9/19/2017 7:27:10 PM
Posted: 2/16/2006 12:15:54 AM EDT
Well, I accidentally fell asleep at 1830, so I am wide awake now

Figured I might as well study, so I was doing some practice problems and came across this doosey. I think I did it right, but I'd just like some confirmation.

I did not switch the > sign because I did not divide by a negative number. So, did I do it right? If not, where did I go wrong?

Thank folks!

Solve the inequality and write the solution set in interval notation:
5 (2 + x) > - 4 (x + 3)

10 + 5x > -4x – 12

10 + 5x + 4x > -4x + 4x – 12

10 + 9x > -12

10 – 10 + 9x > -12 – 10

9x > -22

9x/9 > -22/9

x > -22/9

(-22/9, infinity)
Link Posted: 2/16/2006 12:19:40 AM EDT
[Last Edit: 2/16/2006 12:49:00 AM EDT by Moe-Ron]
I think it is this [-22/9, infinity)

I AM WRONG!!!!!!!!!!!


Cheers
Link Posted: 2/16/2006 12:23:32 AM EDT
According to my book, the bracket is used to mean "equal to or greater than," and parentical citations are for "greater or less than."

But yeah, I got caught on my last project with that and it cost me some points - I used ( ) but because it was equal to or greater than it was supposed to be [ ). Pain in the ass mathematics.

Thanks for the help! At least I know my calculations are correct.
Link Posted: 2/16/2006 12:45:36 AM EDT

Originally Posted By richardh247:
According to my book, the bracket is used to mean "equal to or greater than," and parentical citations are for "greater or less than."

But yeah, I got caught on my last project with that and it cost me some points - I used ( ) but because it was equal to or greater than it was supposed to be [ ). Pain in the ass mathematics!!!!

Thanks for the help! At least I know my calculations are correct.



Wait!! I think you were actually right the first time!!
Link Posted: 2/16/2006 12:48:32 AM EDT
Yeah, well hang tight... I have one more for you if you don't mind.

These are only practice for extra credit for a missed seminar, so it's no big deal. But I'm trying like hell to understand this stuff and soak it all up. Let me finish this one, and then I'll throw it up to see how I did.

And again, thank you for the confirmation. I'm rying like hell to keep a 4.0... One of the few things I am proud of.
Link Posted: 2/16/2006 12:49:47 AM EDT
I don't want to.

Good luck with the math thing.
Link Posted: 2/16/2006 12:51:02 AM EDT

Originally Posted By 4xys2xxs:
I don't want to.

Good luck with the math thing.



Women... Sheesh!



Link Posted: 2/16/2006 12:54:11 AM EDT

Originally Posted By richardh247:
Yeah, well hang tight... I have one more for you if you don't mind.

These are only practice for extra credit for a missed seminar, so it's no big deal. But I'm trying like hell to understand this stuff and soak it all up. Let me finish this one, and then I'll throw it up to see how I did.

And again, thank you for the confirmation. I'm rying like hell to keep a 4.0... One of the few things I am proud of.



If you are getting a 4.0 then you don't need my "help." Math has always been my weak suit, and I am struggling through calculus now, but I'll give it a shot. All the geniuses seems to be absent tonight.
Link Posted: 2/16/2006 1:04:55 AM EDT
42
Link Posted: 2/16/2006 1:11:28 AM EDT
Well, I appreciate it. Yes, I do have a 4.0, but it has been a bitch to keep for these last 2 years. I quit school in 7th grade to work full time, so math is really killing me. It took Camy an entire day to knock into my thick skull the we have to have a LCD for fractions... Yes, I am that math stupid.

The funny thing is that I am an assistant in Corporate Finance, which is a MT 217 level class filled with algebra. That class was tough, but it came naturally to me and I finished with an A. So I thought algebra would be a breeze. Nope. Week 4 and I am struggling with an 86%, so I am after every point I can get. Doing all these practice problems is helping with the concepts, but I need to know if I am doing them right.

So, here's the next one. On this one, isolating x required division by a negative number, so I did switch the sign. What do you think? Did I do ok here, or is it wrong?

Solve the inequality and write the solution set in interval notation:
(3/5)x + (2/3)(x - 5) < x


15(3/5)x + 15(2/3)(x – 5) < x

3x + 10(x – 5) < x

3x + 10x – 50 < x

13x – 50 < x

13x – 13x – 50 < x – 13x

-50 < -12x

-50/-12 < -12x/-12

50/12 > x

25/6 < x

x > -25/6

(-25/6, infinity)
Link Posted: 2/16/2006 1:13:00 AM EDT

Originally Posted By Mr45auto:
42



87 w00t!

Link Posted: 2/16/2006 1:15:40 AM EDT
OK, and one final, last one:

If M (6, 1) is the midpoint of segment PQ and the coordinates of Q are (2, -2), find the coordinates of P.

xm = (x1 + x2) / 2 and ym = (y1 + y2) /2

6 = (x1 + 2) / 2 and 1 = [y1 + (-2)] / 2

12 = x1 + 2 and 2 = y1 + -2

12 – 2 = x1 + 2 – 2 and 2 + 2 = y1 – 2 + 2

10 = x1 and 4 = y1

The coordinates of point P are (10, 4)
Link Posted: 2/16/2006 1:25:18 AM EDT

Originally Posted By richardh247:

(-25/6, infinity)



I got -50/-12 < X : (4.1666, inf)

Cheers
Link Posted: 2/16/2006 1:31:16 AM EDT

Originally Posted By Moe-Ron:

Originally Posted By richardh247:

(-25/6, infinity)



I got -50/-12 < X : (4.1666, inf)

Cheers



Yeah, I had that, too. For some reason, the stupid book wants us to switch the value and the infinity designator (says it makes it easier on the student, but it's just confusing me). Like so:

25/6 < x

x > -25/6

Why do they suggest using the additive inverse and then switching the sign again?
Link Posted: 2/16/2006 1:33:01 AM EDT

Originally Posted By Moe-Ron:

Originally Posted By richardh247:

(-25/6, infinity)



I got -50/-12 < X : (4.1666, inf)

Cheers



One more question (sorry):

In your analysis, wouldn't the infinity sign occur on the left? UGH, I have a headache, and it's only 0330. This is going to be a long friggin day.
Link Posted: 2/16/2006 1:38:51 AM EDT

Originally Posted By richardh247:

Originally Posted By Moe-Ron:

Originally Posted By richardh247:

(-25/6, infinity)



I got -50/-12 < X : (4.1666, inf)

Cheers



Yeah, I had that, too. For some reason, the stupid book wants us to switch the value and the infinity designator (says it makes it easier on the student, but it's just confusing me). Like so:

25/6 < x

x > -25/6

Why do they suggest using the additive inverse and then switching the sign again?



That doesn't make any sense to me because in the first answer x is greater than a positive 25/6, but in the second it has a range into the negative.
Link Posted: 2/16/2006 1:41:34 AM EDT

Originally Posted By richardh247:

Originally Posted By Moe-Ron:

Originally Posted By richardh247:

(-25/6, infinity)



I got -50/-12 < X : (4.1666, inf)

Cheers



One more question (sorry):

In your analysis, wouldn't the infinity sign occur on the left? UGH, I have a headache, and it's only 0330. This is going to be a long friggin day.



I wouldn't call my part in this analysis! I would say no because X is greater than, not lesser.

I hope I was some help.

Cheers
Link Posted: 2/16/2006 1:46:14 AM EDT
[Last Edit: 2/16/2006 1:49:08 AM EDT by Moe-Ron]

Originally Posted By richardh247:
OK, and one final, last one:

If M (6, 1) is the midpoint of segment PQ and the coordinates of Q are (2, -2), find the coordinates of P.

xm = (x1 + x2) / 2 and ym = (y1 + y2) /2

6 = (x1 + 2) / 2 and 1 = [y1 + (-2)] / 2

12 = x1 + 2 and 2 = y1 + -2

12 – 2 = x1 + 2 – 2 and 2 + 2 = y1 – 2 + 2

10 = x1 and 4 = y1

The coordinates of point P are (10, 4)



I think you are right here.

Cheers

BE ADVISED: You MUST have my "answers" verified by someone who is actually competent in math.
Link Posted: 2/16/2006 2:13:22 AM EDT
[Last Edit: 2/16/2006 2:13:56 AM EDT by thehardmaster]


Solve the inequality and write the solution set in interval notation:
(3/5)x + (2/3)(x - 5) < x


15(3/5)x + 15(2/3)(x – 5) < x doesn't 15*(3/5)x=9x not 3x?

3x + 10(x – 5) < x

3x + 10x – 50 < x

13x – 50 < x

13x – 13x – 50 < x – 13x

-50 < -12x

-50/-12 < -12x/-12

50/12 > x

25/6 < x

x > -25/6 I got x>-25/9

(-25/6, infinity)

Link Posted: 2/16/2006 2:40:07 AM EDT

Originally Posted By thehardmaster:


Solve the inequality and write the solution set in interval notation:
(3/5)x + (2/3)(x - 5) < x


15(3/5)x + 15(2/3)(x – 5) < x doesn't 15*(3/5)x=9x not 3x?

3x + 10(x – 5) < x

3x + 10x – 50 < x

13x – 50 < x

13x – 13x – 50 < x – 13x

-50 < -12x

-50/-12 < -12x/-12

50/12 > x

25/6 < x

x > -25/6 I got x>-25/9

(-25/6, infinity)




Nice catch bro! Thank you! How in the hell did I mess that up?
Link Posted: 2/16/2006 2:43:44 AM EDT
[Last Edit: 2/16/2006 2:44:28 AM EDT by thehardmaster]

Originally Posted By richardh247:


Nice catch bro! Thank you! How in the hell did I mess that up?



No problem. I hate when I am doing trig/calc/diff eq and I have no trouble with the advanced concepts, but I make a simple arithmetic error that costs me all of the points. Happens to me all of the time.
Link Posted: 2/16/2006 2:51:32 AM EDT
OK, so, let's try this again?

Man, thanks so much for the help! I really screwed the pooch on this one.

OK, we have to show a multiplication by LCD of all terms - we are not allowed to just add the fractions (don't ask me why bro). So, here is how I did it using your revisions.

15(3/5)x + 15(2/3)(x – 5) < 15x

9x + 10(x – 5) < 15x

9x + 10x – 50 < 15x

19x – 50 < 15x

19x – 19x – 50 < 15x – 19x

-50 < -4x

-50/-4 < -4x/-4

50/4 > x

25/2 < x

x > -25/2

(-25/2, infinity)

Is this right then?
Link Posted: 2/16/2006 2:59:39 AM EDT
[Last Edit: 2/16/2006 3:04:21 AM EDT by thehardmaster]
never mind, answered my own question. You are right. (-25/2, infinity) seems to be right.
Link Posted: 2/16/2006 3:36:04 AM EDT
Either one of you two have a glock pistol? I have a way to say thank you with a brand new Pearce Grip Glock grip frame insert if you think you can use it. I won it as a prize, but I don't own any Glocks. I'll give it to you if you can use it - supposed to fit any model Glock pistol.

I won't even ask for shipping. Just a way of saying thank you.

First one of you two to post here and send me a PM with your address gets it mailed out today.

Thanks again, guys! You have both been a great help!
Link Posted: 2/17/2006 5:17:13 PM EDT
If its free its on me!
Top Top