How do you evaluate the expression for x = -2, y = 3, z = -4 given 7x - 2y - 8z?

Apr 24, 2016

12

Explanation:

Substitute the numbers into its corresponding position.
$7 \left(- 2\right) - 2 \left(3\right) - 8 \left(- 4\right)$

Now evaluate using PEMDAS (Remember that when multiplication and division are together evaluate from left to right. The same thing goes for addition and subtraction.)
$7 \left(- 2\right) - 2 \left(3\right) - 8 \left(- 4\right)$
$= - 14 - 2 \left(3\right) - 8 \left(- 4\right)$
$= - 14 - 6 - 8 \left(- 4\right)$
$= - 14 - 6 + 32$
$= - 20 + 32$
$= 12$