Toán 1.3x^2-7x+76 2.2x^2-7X+3 3.x^3-8x^2+x+42 07/07/2021 By Remi 1.3x^2-7x+76 2.2x^2-7X+3 3.x^3-8x^2+x+42
1.3x^2-7x+76 vô nghiệm 2.2x^2-7X+3 =2x^2-6x-x+3 =2x(x-3)-(x-3) =(2x-1)(x-3) 3.x^3-8x^2+x+42 =x^3-7x^2-x^2+7x-6x+42 =x^2(x-7)-x(x-7)-6(x-7) =(x^2-x-6)(x-7) =(x^2-3x+2x-6)(x-7) =(x-3)(x+2)(x-7) Trả lời
1.3x^2-7x+76
vô nghiệm
2.2x^2-7X+3
=2x^2-6x-x+3
=2x(x-3)-(x-3)
=(2x-1)(x-3)
3.x^3-8x^2+x+42
=x^3-7x^2-x^2+7x-6x+42
=x^2(x-7)-x(x-7)-6(x-7)
=(x^2-x-6)(x-7)
=(x^2-3x+2x-6)(x-7)
=(x-3)(x+2)(x-7)