Factor. x^3+5x^2-4x-20

(x+5) (x+2) (x-2); For this we can use factoring by grouping. Simply split the equation in 2 and factor out any terms. Then combine both the coefficients and the expression in parentheses (which should be the same.

x^3+5x^2. - 4x-20

x^2 (x+5). - 4 (x+5)

After combining the 2 expressions, we have a difference of squares (x^2-4) meaning a subtraction expression and both the terms in it are perfect squares. To factor, put the square root of both terms plus and minus each other in separate equations.

The final answer should be (x+5) (x+2) (x-2)