The denominator can't equal zero. Factor the denominator: x^2 - 3x - 28= (X - 7)(x + 4); next set each set of parentheses equal to 0; x - 7 = 0; so x=7 is one value x + 4 = 0; so x=-4 is the other Remember, x = 7 and x= -4 make the denominator zero, which is a "restriction" because you can't divide by zero.
