Finding the zeros of $f(x)=-x^3-x^2+7x+7$

Question

$$f(x)=-x^3-x^2+7x+7$$ it needs to be solved for the zeros I need to figure out the answer to this please help I have tried many different things and I'm confused

Answer 1

Hint: $$-x^3-x^2+7x+7=(-x^2+7)(x+1).$$

Answer 2

Hint: $$-x^3-x^2=(-x^2)(x+1)\qquad \qquad\qquad7x+7=7(x+1)$$

Answer 3

Try grouping pairs of terms together like so:$$f(x)=\underbrace{-x^3-x^2}+\underbrace{7x+7}$$Observe $-x^3-x^2=-x^2(x+1)$ and $7x+7=7(x+1)$ hence$$f(x)=-x^2(x+1)+7(x+1)=(x+1)(\dots)$$