Question

When finding the product (x – 3)(x + 4), what would you add to xsquared-3x to get the final answer?
A.
–4x + 12
B.
–3x – 12
C.
3x + 12
D.
4x – 12

Answer 1

Well, what is (x – 3)(x + 4) expanded?

Answer 2

i have no idea

Answer 3

what u mean expand

Answer 4

:), Ok, use the FOIL method. Multiply the two First ones, together, then the Outside ones, then the Inside ones, and then the Last ones and then add them all together. What do you get?

Answer 5

okay thanks

Answer 6

i think D but i may have done it wrong

Answer 7

See http://www.khanacademy.org/math/algebra/polynomials/multiplying_polynomials/v/multiplying-binomials

if you want to learn how to do this

Answer 8

thanks

Answer 9

Well lets see. (x – 3)(x + 4) = x^2 + 4x - 3x -12
=x^2 + x -12 ...(1)
So to get from x^2 - 3x to (1), you need to add 4x - 12. So D is indeed correct!

Answer 10

thanks you

Answer 11

You're welcome :)