Factor to find the zeros of the function defined by the quadratic expression 4x2 − 24x − 108 .

First, divide the expression by 4 to eliminate the numerical coefficient of the first term.
                              x² - 6x - 27
For quadratic expression, 
                                  a + b = -B = 6
                                     ab = C = -27
The values of a and b in the equations above is 9 and -3.