The solution for quadratic equation is
S = { +√(225/4) , -√(225/4) }.
4x^2 - 225 = 0
4x^2 = 0 + 225
4x^2 = 225
x^2 = 225/4
x = ±√(225/4)
x' = +√(225/4)
x'' = -√(225/4)
Therefore , the solution for quadratic equation is S = { +√(225/4) , -√(225/4) }.