6(2x+1)²-13(2x+1)-15=0
6(4x²+4x+1)-26x-13-15=0
24x²+24x+6-26x-13-15=0
24x²-2x-22=0
12x²-x-11=0
(x-1)(12x+11)=0
x-1=012x+11=0
x1=1x2=-11/2