Question

Which value of k makes (2x + 3)(kx – 5) = 2kx^2 – x – 15 true?

A. –3

B. –1

C. 1

D. 3

Answer 1

Can anybody help?

Answer 2

well you're going to have to expand the left side on this one

Answer 3

then see if the x's will cancel somehow so you can solve for k

Answer 4

I have to try the values right?

Answer 5

well you could do that, but it is not necessary

Answer 6

then how should I solve it?:(

Answer 7

Simplify LHS,
tell us what you get

Answer 8

2kx^2 +3kx - 10x -15 = 2kx^2 - x - 15

k(2x^2 + 3x) - 10x - 15 = 2kx^2 - x = 15

subtract 2kx^2 - 10x - 15 from both sides

3kx = 9x

divide by 3x on both sides

k = 3

Answer 9

Thank you!!!

Answer 10

you're welcome, that one was a little tricky, just know that you have to be able to get rid of the x variable somehow and leave a constant behind