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?

Re: Accuplacer practice exam help

Fill in:

$\displaystyle 2.2^2+3.2.(-4)-4.(-4)^2=8-24-64=-80$

Re: Accuplacer practice exam help

Quote:

Originally Posted by

**Siron** Fill in:

$\displaystyle 2.2^2+3.2.(-4)-4.(-4)^2=8-24-64=-80$

@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 $\displaystyle 2\cdot 2^2+3\cdot 2\cdot (-4)-4\cdot (-4)^2=8-24-64=-80$ .

Re: Accuplacer practice exam help

Re: Accuplacer practice exam help

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

I appreciate it!