(7X-2)²=4(X-1)²
(7X-2)²-4(X-1)² =0
(7X-2)²-(2X-2)² =0
（7X-2+2X-2）（7X-2-2X+2）=0
（9x-4）（5x）=0
x=4/9或者x=0