45x(x-25)=16怎么解

题目

45x(x-25)=16怎么解

答案

x(x-2/5)=20
x²-2x/5=20
x²-2x/5+1/25=20+1/25=501/25
(x-1/5)²=(±√501/5)²
x-1/5=±√501/5
x=(1-√501)/5,x=(1+√501)/5