1)x²-x-12=х²-9-(х+3)=(х-3)(х+3)-(х+3)=(х-3-1)(х+3)=(х-4)(х+3) 2)х²-10х+16=х²-8х-2х+16=х(х-8)-2(х-8)=(х-2)(х-8) 3)25a²-70ab+49b²=25а²-35ab-35ab+49b²=5a(5a-7b)-7b(5a-7b)=(5a-7b)(5a-7b) 4)1/5x²-11/5+6=1/5x²+19/5=1/5(x²+19) 5)15x2-11+2=15x²-9=3(5x²-3) 6);4x²-x-3 =3x²+x²-x-3=3(x²-1)+x(x-1)=3(x+1)(x-1)+x(x-1)=(3(x+1)+x)(x-1)=(3x+3+x)(x-1)=(4x+3)(x-1)