Question

I'm trying to teach myself Algebra over the summer. Can someone explain this problem to me? "The factored expression (m+7) (m-11) is equivalent to the expanded form m^2 - 4m - 77. When m=6, the value of m^2 - 4m - 77 is a multiple of 13. Why is this?

Answer 1

which part is not clear?

Answer 2

I don't know why it is always a multiple of 13. That's what I don't understand.

Answer 3

just replace m with 6

6^2 - 4*6 - 77 =.....

I think you'll find the answer is a multiply of 13..... the other factor is negative

Answer 4

(m+6) if m=7 is 7+6=13 so we have 13*something
So its a multiple of 13

Answer 5

I still don't get it, I'm sorry.

Answer 6

the factorized for is (m+6)*(m-11)
now if m=7 that is
(7+6)*(7-11)=13*(-4)

Answer 7

that means that it is a multiple of 13 as you can pull that number out

Answer 8

oh...I get it now, Thank you so much!