25(1+2x)^2=16(x-6)^2
25(1+2x)^2-16(x-6)^2=0
[5(1+2x)+4(x-6)][5(1+2x)-4(x-6)]=0
(14x-19)(6x+29)=0
14x-19=0,或6x+29=0
x=19/14,或x=-29/6