(2x+1)²-[2(x-3)]²=(2x+1)²-(2x-6)²=(2x+1+2x-6)(2x+1-2x+6)=7(4x-5)=28x-35
(2x+1)²-2(x-3)²=(2x-1)(x+5)+234x²+4x+1-2x²+12x-18=2x²+9x-5+232x²+16x-17=2x²+9x+1816x-17=9x+1816x-9x=18+177x=35x=5
