Accuplacer practice exam help

Hello board. I'm trying to solve the problems on the accuplacer practice exam online and am having trouble with one of the questions. It is:

What is the value of the expression 2x² + 3xy – 4y² when x = 2 and y = - 4?

The answer I keep coming up with is -4. The only choices are -80, 80, -32, and 32.

What am I doing wrong?

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Originally Posted by Siron

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@Siron, here is a LaTeX suggestion:
[tex]2\cdot 2^2+3\cdot 2\cdot (-4)-4\cdot (-4)^2=8-24-64=-80[/tex] gives .

Thanks for the notice.

Thanks guys....I guess I was retaining the original values and not changing them.
I appreciate it!