Posted: 10/12/2010 11:28:40 AM EDT
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I need some help with this problem.
|-3x+1/5|=6 Thus far I realize is it going to be +- 6 and I subtract 1/5 from each but I get an improper fraction or mixed number and dividing that by 3 doesn't really help me for plotting interval notation. |
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Quoted:
I need some help with this problem. |-3x+1/5|=6 Thus far I realize is it going to be +- 6 and I subtract 1/5 from each but I get an improper fraction or mixed number and dividing that by 3 doesn't really help me for plotting interval notation. |-3x+1/5| = 6 -3x+1/5 = +- 6 -3x = (+-6) - 1/5 -3x = +6 - 1/5 or -6 -1/5 -3x = +29/5 or -31/5 x = (+29/5)/-3 or (-31/5)/-3 x = -29/15 or +31/15 ETA interval notation: [-29/15] U [31/15] |
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Quoted:
I need some help with this problem. |-3x+1/5|=6 Thus far I realize is it going to be +- 6 and I subtract 1/5 from each but I get an improper fraction or mixed number and dividing that by 3 doesn't really help me for plotting interval notation. I always liked to do it with a double equality. -6 = -3x+1/5 = 6 -31/5 = -3x = 29/5 31/15 = x = -29/15 |
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Quoted:
Quoted:
I need some help with this problem. |-3x+1/5|=6 Thus far I realize is it going to be +- 6 and I subtract 1/5 from each but I get an improper fraction or mixed number and dividing that by 3 doesn't really help me for plotting interval notation. I always liked to do it with a double equality. -6 = -3x+1/5 = 6 -31/5 = -3x = 29/5 31/15 = x = -29/15 I'm liking this looks like something I can understand. So for another one such as |2x/3-2|>=7. Would I make the seven positive and negative. Add 2 to the seven. Then multiply it by 3 to get 2x>=9, and 2x<=-15 then divide by 2? My specific problem is when I multiply the 3 and the two x does it just become 2x or 6 x? |
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The only concern with the 3-column method is that you have to be careful not to confuse the left and right answers.
In the second example, it would be: |2x/3-2|>7 -7 > 2/3*x - 2 > 7 -5 > 2/3*x > 9 -15/2 > x > 27/2 Note that you must flip the inequality on the left side to begin. And don't confuse the answer with a window. It's actually x > 27/2 OR x < -15/2 |