Question

-4|x+5y| for x=7 and y=-3

Answer 1

The answer is negatif 32

Answer 2

First of all, let's plug the values. You simply have to substitute every occurrence of "x" with "7" and every occurrence of "y" with "-3", which leads to

$-4|x+5y| \to -4|7+5\cdot (-3)| = -4|7-15| = -4|-8|$

Now, the absolute value of a number $x$, i.e. $|x|$, returns the positive versione of a number. So, if x is positive, you have $|x| = x$ whereas if x is negative you have $|x| = -x$.

In this case, the absolute value of -8 is 8, because -8 is negative. So, the expression becomes

$-4|-8| = -4 \cdot 8 = -32$