(6х+7)(6х-7)+12х=12х(3х+1)-49

(6x+7)*(6x)+12x=12x*(3x+1)-4936x²-49+12x=36x+12x-4936x²-36x=0  I÷36x²-1=0x=1    x=-1.

(6x+7)(6x-7)+12x=12x(3x+1)-49 +12x=36x+12x-49 +12x-12x-36x+=0[tex] 6x^{2} - 36x=06x(x-6)=06x=0         x-6=0x=0           x=6