simplify (3x^2-5x+4)-(5x^2+7x-7)

Answer 1

Combine similar terms. For example, the two "x^2" terms combine to give
3x^2 -5x^2 = -2x^2

You can also combine the two 'x' terms, to get one 'x' term and the two constants also.

Don't forget that the "-" in front of
(5x^2+7x-7) changes the sign of every term inside the parentheses, before you combine similar terms.

You should end up with
-2x^2 -12x +11