Question

Find 2x2 − 2z4 + y2 − x2 + z4 if x = −4, y = 3, and z = 2. Is -3 the correct answer?

Answer 1

We're given the algebraic expression 2x^2 - 2z^4 + y^2 - x^2 + z^4

By hypothesis, x = -4, y = 3 and z = 2

Let's replace each letter by its given value:

2x^2 - 2z^4 + y^2 - x^2 + z^4
2(-4)^2 - 2(2)^4 + (3)^2 - (-4)^2 + (2)^4
(2*16) - 2*16 + 9 - 16 + 16
32 - 32 + 9 - 16 + 16
9

So wrong. The correct answer is not -3, but 9.

Hope this helps! :D