(3x)^2+10^2=(7x-10)^2

问题描述:

(3x)^2+10^2=(7x-10)^2

9x^2+100=49x^2-140x+100
40x^2-140x=0
x^2-3.5x=0
x(x-3.5)=0
x=0,x=3.5