Assuming that the denominator on the right side of the equation is w+7, you must multiply both top and bottom of the right side of the equation by (-1) giving w-5/(w+7) which would mean that the blank in your equation is equal to (w-5) because the denominator on the left side and the denominator on the right side of the equation are equal and there is no numerator on the right side of the equation except for the blank.
