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2 < 2x - 1 < 7

I got x < 4.

Right or wrong?

2007-11-15 03:29:09 · 3 answers · asked by wrongnumber 1 in Science & Mathematics Mathematics

3 answers

You solved 2x-1 < 7 correctly.

but think about ALL numbers less than four (like negative one billiion!) Will they all make 2x -1 greater than 2? No.

(this is how you can check your own answers to see if they are reasonable. If your solution is a one sided inequality, try an "extreme' example to see if it still works.)

so you need to also find x 's which are also solutions to
2 < 2x -1.

the previous posters show how to solve both inequalities at the same time.

2007-11-15 03:36:57 · answer #1 · answered by Michael M 7 · 0 0

Wrong.

2 < 2x - 1 < 7
3<2x<8
1.5

2007-11-15 03:32:21 · answer #2 · answered by Sciman 6 · 0 0

add 1 to all 3 slots
3<2x<8
divide 2 on all 3 slots
3/2

2007-11-15 03:32:04 · answer #3 · answered by someone else 7 · 0 0

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