Expand collect like terms:

x(x+7)+4(x^2-5)

=x^2+7x+4x^2-20

= 5x^4+7x-20

i'm not sure if i'm was suppose to add the exponents together to make 5x^4

or 5x^2

2. It should have been $5x^2$, but apart from that you are completely right.

3. Do not add the exponents!

x^2 + 4x^2 = 5x^2

4. thanks guy, really appreciate the help