X(x+7)=4(6+4)
x^2 + 7x = 24 + 16
x^2 + 7x -40 = 0
a=1 b=7 c=-40
Using the quadratic formula:
x = [-7 +- sq root(49 -4*1*-40)] / 2*1
x = [-7 +- sq root (209)] / 2
x1 = [-7 +14.4568322948] / 2
x1 = 3.7284161474
x2 = [-7 -14.4568322948] / 2
x2 = -10.7284161474