Question

Factor a2 + 4ab – 45b2 on your paper. Which one of these is a factor of the trinomial?


(a + 3b)

(a – 9b)

(a – 5b)
none of the above

Answer 1

a-9b

Answer 2

Just to make sure, they want you to factor \(a^2+4ab-45b^2\) , right?

Answer 3

Can u see how?

Answer 4

a^2+9ab-5ab-45b^2
a(a+9b)-5b(a-9b)
(a+9b)(a-5b)

Answer 5

yeah, I see it as +9 and -5 too

Answer 6

a^2 + 4ab - 45b^2
(a^2 + 9ab) ( -5ab -45b^2)
a( a + 9b) -5b ( a +9b)

a - 5b) (a +9 b)

So the third one