Question

(6x+7)×(6x-7)+12x=12x(3x+1)-49

Answer 1

(6х+7)*(6х-7)+12х=12х(3х+1)-49;
36х-49+12х=36х+12х-49;
36х+12х-36х-12х=-49+49;
0=0.
Вроде так.