# Accuplacer practice exam help

• Jul 15th 2011, 08:28 AM
Troxartes
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?
• Jul 15th 2011, 08:39 AM
Siron
Re: Accuplacer practice exam help
Fill in:
$2.2^2+3.2.(-4)-4.(-4)^2=8-24-64=-80$
• Jul 15th 2011, 09:11 AM
Plato
Re: Accuplacer practice exam help
Quote:

Originally Posted by Siron
Fill in:
$2.2^2+3.2.(-4)-4.(-4)^2=8-24-64=-80$

@Siron, here is a LaTeX suggestion:
$$2\cdot 2^2+3\cdot 2\cdot (-4)-4\cdot (-4)^2=8-24-64=-80$$ gives $2\cdot 2^2+3\cdot 2\cdot (-4)-4\cdot (-4)^2=8-24-64=-80$ .
• Jul 15th 2011, 09:13 AM
Siron
Re: Accuplacer practice exam help
Thanks for the notice.
• Jul 15th 2011, 09:53 AM
Troxartes
Re: Accuplacer practice exam help
Thanks guys....I guess I was retaining the original values and not changing them.
I appreciate it!