Question

Which of the following is equivalent to (5x-2)(-4x+9)?

*it’s free response question

Answer 1

Use distributive property: (a + b)(c + d) = ac + ad + bc + bd.

`(5x-2)(-4x+9)=(5x)(-4x)+(5x)(9)+(-2)(-4x)+(-2)(9)\\\\=-20x^2+45x+8x-18=\boxed{-20x^2+53x-18}`

Answer 2

-20x^2 + 53x -18

Step-by-step explanation:

FOIL

First terms

Outer terms

Inner terms

Last terms

So lets do our F:

5x * -4x = -20x^2

Now lets do our O:

5x * 9 = 45x

Now lets do our I:

-2 * -4x = 8x

Now lets do our L:

-2 * 9 = -18

Lets put all those together:

-20x^2 + 45x + 8x - 18

Combine like terms:

-20x^2 + 53x -18