calculus
posted by John .
Let f(x)=–5x(x–5).
Then f'(–1)=
And after simplifying f'(x)=
Hint: You may want to expand and simplify the expression for f(x) first.

John, I really believe that anybody who studies Calculus should be able to do an easy question such as this.
f(x) = 5x^2  25x
I will let you take it from there