(x-7)(x+3)+(x-1)(x+5)=4x
问题描述：
(x-7)(x+3)+(x-1)(x+5)=4x
答
(x-7)(x+3)+(x-1)(x+5)=4x
x^2-4x-21+x^2+4x-5=4x
2x^2-4x-26=0
x^2-2x-13=0
x=[1±√14]