algebra

Well f(-1) is just the value of f(x) when x=-1, or the value of 4x²+5x+7 when x=-1 since f(x)=4x²+5x+7. So just substitute -1 for x in the quadratic and do the arithmetic.

4x²+5x+7 4(-1)²+5(-1)+7 4+-5+7=6

Therefore f(-1)=6. Hope that helps.