You can put this solution on YOUR website! f(x) = -x^3 + x^2 + 3x + 4
For f(0), you would set x to zero. ... Hence: f(x = 0) = f(0)
f(0) = -0^3 + 0^2 + 3*0 + 4 = 4
Same with f(1) = f(x = 1)
f(1) = -1^3 + 1^2 + 3*1 + 4 = -1 + 1 + 3 + 4 = 7
Now, you try f(-1).