E(x)=4x²-1-(x²-4x+4)-(x²-1)+10=4x²-1-x²+4x-4-x²+1+10=2x²+4x+6=2(x²+2x+3)
E(1)=2(1+2+3)=2*6=12
x²-x-2=x²-1-x-1=(x²-1)-(x+1)=x-1)(x+1)-(x+1)=(x+1)(x-1-1)=(x+1)(x-2)
x²+x-2=x²-1+x-1=(x-1)(x+1)+(x+1)=(x+1)(x-1+1)=x(x+1)
x²-2x-3=x²-1-2x-2=(x-1)(x+1)-2(x+1)=(x+1)(x-1-2)=(x+1)(x-3)
x²+2x-3=x²-1+2x-2=(x-1)(x+1)+2(x-1)=(x-1)(x+1+2)=(x-1)(x+3)