Toán Lớp 8: tính -4x(x+3)(x-4)-3x(x^2-x+1) 4x(x^2-x+3)-(x-6)(x-5) -3(x+1)(x-7)+7(x-5)(x-1) ai làm nhanh em cho trlhn ạ

Question

Toán Lớp 8:  tính  -4x(x+3)(x-4)-3x(x^2-x+1) 4x(x^2-x+3)-(x-6)(x-5) -3(x+1)(x-7)+7(x-5)(x-1) ai làm nhanh em cho trlhn ạ

ngoclandiep · Answer

Giải đáp:       Lời giải và giải thích chi tiết:      $ text{-4x(x+3)(x-4)-3x(x&sup2;-x+1)}$   $ text{= (-4x&sup2;-12x)(x-4)-3x&sup3;+3x&sup2;-3x}$   $ text{= -4x&sup3;+16x&sup2;-12x&sup2;+48x-3x&sup3;+3x&sup2;-3x}$   $ text{= -7x&sup3;+7x&sup2;+45x}$      $ text{4x(x&sup2;-x+3)-(x-6)(x-5)}$   $ text{= 4x&sup3;-4x&sup2;+12x-x&sup2;+5x+6x-30}$   $ text{= 4x&sup3;-5x&sup2;+21x-30}$      $ text{-3(x+1)(x-7)+7(x-5)(x-1)}$   $ text{=(-3x-3)(x-7)+(7x-35)(x-1)}$   $ text{=-3x&sup2;+21x-3x+21+7x&sup2;-7x-35x+35}$   $ text{= 4x&sup2;-24x+56}$

hauthanhyen98 · Answer

a, -4x(x+3)(x-4)-3x(x^2-x+1)      =-4x&sup2;-12x-4x&sup2;+16x-3x&sup3;+3x&sup2;-3x     =(-4x&sup2;-4x&sup2;+3x&sup2;)+(-12x+16x+3x)-3x&sup3;     =-5x&sup2;+x=3x&sup3;     b,4x(x^2-x+3)-(x-6)(x-5)      =4x&sup3;-4x&sup2;+12x-x&sup2;+5x+6x-30     =4x&sup3;-5x&sup2;+21x-30     c,-3(x+1)(x-7)+7(x-5)(x-1)     =-3.(x+1).(x-7)+7(x-5).(x-1)     =(-3x-3).(x-7)+(7x-35).(x-1)     =-3x&sup2;+21x-3x+21+7x&sup2;-7x-35x+35     =4x&sup2;-24x+56