Ok, here is my question. Its on my homework and my Professor won't help us with this one, but I just don't get it!
(r+s)^2-16
Now what I was thinking was taking the square of the entire thing, that way eliminating the square and making the -16 a -4, but my Professor keeps saying u=r+s so I should substitute it. My thought is, where did u come from????
the other one I was wondering about was this:
-x(x^2+1)-3x^2(4x-9)
as an answer I got: -11x^3-27x^2-x but I don't know if that's right.
If you can help me at all, please reply. Thanks
(r+s)^2-16
Now what I was thinking was taking the square of the entire thing, that way eliminating the square and making the -16 a -4, but my Professor keeps saying u=r+s so I should substitute it. My thought is, where did u come from????
the other one I was wondering about was this:
-x(x^2+1)-3x^2(4x-9)
as an answer I got: -11x^3-27x^2-x but I don't know if that's right.
If you can help me at all, please reply. Thanks