Question

$(x-3)(x+4)-2(3x-2)=(x-4) ^{2}$(x-3)(x+4)-2(3x-2)=(x-4)

Answer 1

$x^{2} +4x-3x-12-6x+4= x^{2} -8x+16 \\ -5x+4+8x-16=0 \\ 3x-12=0 \\ 3x=12 \\ x=4$
S={4}

Answer 2

x²+4x-3x-12-6x+4=x²-8x+16
x²-5x-8=x²-8x+16
x²-5x-8-x²+8x-16=0
3x-24=0
3x=24⇒x=8