Question

Which of the following is a factor of the polynomial x^2-x-20?

A. x-5
B. x-4
C. x+2
D. x+5
E. x+10

Answer 1

do you know how to factor it first?

Answer 2

I can't for the life of me remember how to do it. I haven't had a math class in roughly two years, and I have to take a placement test for class soon, so I've been doing some prep.

Answer 3

ok what 2 numbers multiply together =20 and add together =1

Answer 4

-5 and 4

Answer 5

\(\large \begin{array}{cccllll}
x^2&-x&-20\\
&\uparrow&\uparrow \\
&4-5&4\cdot -5
\end{array}\)

Answer 6

correct. so now you have x^2-x-20=0-----> (x-5) and (x+4) now all u have to do is to check which one will give you 0

Answer 7

-5

Answer 8

yeap

Answer 9

u got it :D

Answer 10

you know why "2 numbers multiply together =20 and add together =-1"?