Đáp án:
Giải thích các bước giải:
a, 2(3x-1)(2x+5)-6(2x-1)(x+2)=-6
2(6x²+15x-2x-5)-6.(2x²+4x-x-2)=-6
12x²+30x-4x-10-12x²-24x+6x+12=-6
(12x²-12x²)+(30x-4x-24x+6x)+(-10+12)=-6
8x+2=-6
8x=-6-2
8x=-8
x=-8:8
x=-1
b, 2x(x²-2)+x²(1-2x)-x²=-12
2x³-4x+x²-2x³-x²=-12
(2x³-2x³)-4x+(x²-x²)=-12
-4x=-12
x=-12:-4
x=3
c, 4(2-x)+x(x+6)=x²
8-4x+x²+6x=x²
8+(-4x+6x)+x²=x²
8+2x+x²=x²
8+2x=0
2x=-8
x=-4
d, 4x(x-1)-3(x²-5)-x²=-7
4x²-4x-3x²+15-x²=-7
(4x²-3x²-x²)-4x+15=-7
-4x+15=-7
-4x=-22
x=$\frac{11}{2}$