Algebra

[jenae.dunlop]

In Chapter 8 of the "5 pound book of GRE practice problems," on p.356, I'm confused about question 9:

8-2(-4 + 10x)/ 2-x = 17, what is the value of x?

Rather than subtracting 2 from 8, and then multiplying 6 by both terms within the parentheses in the numerator, the answer key simplifies the numerator on the left hand side of the equation as follows: 8 + 8 - 20x. So it appears as though the -2 has been multiplied by -4 and by 10x, and the 8 has just been left as 8. According to what rule of algebra is this correct? I thought that the "8-2" should be simplified to be 6, prior to multiplying by the terms within the parentheses...

Thanks for the clarification!!

[tommywallach]

Hey Jenae,

PEMDAS is your order of operations:

Parentheses/exponents/multiplication/division/addition/subtraction

In other words, you MUST multiply before you do any addition or subtraction. If I write:

4 - 2 * 6

You have to do the 2*6 portion first.

Hope that helps!

-t