Разложите на множители квадратный трёхчлен: 1) -15x^2+2x+1; 2) -12x^2+7x-1; 3)-16x^2+8x+3; 4)27x^2-6x-1.

1) -15x^2+2x+1 = -15(х +1/3)(х +1/5) = (-х -1)(5х+1) ;
2) -12x^2+7x-1 = -12(х - 1/3)(х -1/4) = (-3х +1)(-4х +1);
3)-16x^2+8x+3 = -16(х -3/4)(х +1/4) = (-4х +3)(4х +1);
4)27x^2-6x-1 = 27(х - 1/3)(х +1/9) = (3х-1)(9х +1)