Simplify 4(7-10)^2 / (-6) - 5 * (-2)

Question

I have been getting -16 for the answer on this problem, yet when plugged into a calculator the answer is +4. I was wondering the reason for this and if someone could explain more in-depth of why.

Answer 1

Maria, Yefim and Todd have shown how to do it, and I suspect you know everything they said, or you would have got any of several different wrong answers. I suspect that the reason you got -16 instead of +4 is a simple error right at the end: you multiplied (-5) by (-2) and incorrectly got (-10).

In other words, you did the hard stuff right, and “dropped a sign”, an easy mistake.

Answer 2

Yefim,

This is a question of the precedence of mathematical operations (PEMDAS) so...

1. Paranthetical terms - 3, -6, -2
2. Exponents -3^2 = 9
3. Multipication 4x9 = 36, -5x-2 = -10
4. Division 36/-6 = -6
5. Addition
6. Subtraction -6 - -10 = 4, this is equivalent to -6 + 10

Hope this helps you see how to break down a problem with multiple mathematical operations.

Regards,

Todd

Answer 3

Given expression equel 4(-3)²/(- 6) - 5(-2) = 36/(-6) + 10 = - 6 + 10 = 4