(x+4)(x+5)=20

To solve the equation (x+4)(x+5) = 20, we can first expand the left side of the equation.

(x+4)(x+5) = x(x+5) + 4(x+5) = x^2 + 5x + 4x + 20 = x^2 + 9x + 20

Now we have the equation x^2 + 9x + 20 = 20.

To solve for x, we can subtract 20 from both sides of the equation:

x^2 + 9x + 20 - 20 = 20 - 20

Simplifying:

x^2 + 9x = 0

Now, set the equation equal to zero and look for factors:

x(x + 9) = 0

To find the values of x, we set each factor equal to zero:

x = 0 or x + 9 = 0

The solutions are x = 0 and x = -9.