Question

Factor 4a2 - 25.



(2a + 5)(2a + 5)
(2a - 5)(2a - 5) ******
(2a - 5)(2a + 5)
I think it is the one with the *******

Answer 1

I dont think so. If you multiply it out using FOIL method, you'll see that it doesn't give you the original function. Try again.

Answer 2

okay is it the 3rd one

Answer 3

I don't know, did you try multiplying it out to see if you get the original function? :)

Answer 4

I tried
so it is the first one

Answer 5

I don't think you tried at all because the answer isn't the first one. it's the 3rd one.

Answer 6

When you multiply everything out, you should see that the numbers you get when you have: \[ax^2+bx+c \]
since you're missing bx, that tells you that your two b' numbers MUST be ZERO!\[(ax+c)(ax-c) = ax^2-c\]