Question 600415
Replace 'x' with -1 and evaluate/simplify to find the answer.


-4x^3+8x^2-9x-1


-4(-1)^3+8(-1)^2-9(-1)-1


-4(-1)+8(1)-9(-1)-1


4+8+9-1


20



So -4x^3+8x^2-9x-1 = 20 when x = -1