a) (x-1)(x+1)=2(x-3)²-x²
x²-1²=2(x²-6x+9)-x²
x²-1-2x²+12x-18+x²=0
12x-19=0
12x=19
x=19/12
b) (2x+3)²-4(x-1)(x+1)=49
4x²+9+12x-4(x²-1²)=49
4x²+9+12x-4x²+4-49=0
12x-36=0
12x=36
x=3
a) (x-1)(x+1)=2(x-3)²-x²
x²-1²=2(x²-6x+9)-x²
x²-1-2x²+12x-18+x²=0
12x-19=0
12x=19
x=19/12
b) (2x+3)²-4(x-1)(x+1)=49
4x²+9+12x-4(x²-1²)=49
4x²+9+12x-4x²+4-49=0
12x-36=0
12x=36
x=3