(x-2)(x+4)+3(x-8)=x²+4x-2x-8+3x-24=x²+5x-32
2(x-3)-5(x-1)(x-5)=2x-6-5(x-1)(x-5)=2x-6-5(x²-5x-x+5)=2x-6-5x²+25x+5x-25=-5x²+32x-31
A=(1/4)²+5x1/4-32=1/16+5/4-32=1/16+20/16-512/16=-491/16
B= -5(-1)²+32(-1)-31=-5x1-32-31=-5-32-31=-68
factoriser : (x-2)[(x+4)-(x-8)]
(2x+3)[(x-7)+(x-9)]