Question

If 5 less than double a number is between -7 and 13

Answer 1

Firstly, we will let this mystery number we are finding be labelled as x. Double this number can be written as 2x. 5 less than double this number is written as 2x - 5. And because this number is between -7 and 13, we have the full inequality, -7 < 2x - 5 < 13.

To solve this inequality, we want to isolate x, so we add 5 to all 3 parts of the inequality. Doing so cancels out the - 5 in the middle, so our new inequality is -2 < 2x < 18. Now we want to divide all 3 parts of the inequality by 2 to isolate x, so now our final inequality is -1 < x < 9. Thus, we can say that x is between -1 and 9.