Toán Lớp 8: câu1:x mũ2-xy+x-y câu2;(x-y).(x+y) câu3.(x-2).(x+2)-x.(x-1) câu4.x mũ 2-xy+x-y câu5.(x+y)mũ2 câu6. (x+y)mũ3

Question

Toán Lớp 8:  câu1:x mũ2-xy+x-y câu2;(x-y).(x+y) câu3.(x-2).(x+2)-x.(x-1) câu4.x mũ 2-xy+x-y câu5.(x+y)mũ2 câu6. (x+y)mũ3

cobelolen · Answer

Giải đáp+Lời giải và giải thích chi tiết:      C&acirc;u 1:     x&sup2;-xy+x-y     = (x&sup2;+x)-(xy+y)     = x.(x+1)-y.(x+1)     = (x+1).(x-y)     C&acirc;u 2:     (x-y).(x+y)     = x&sup2;-y&sup2;     C&acirc;u 3:     (x-2).(x+2)-x.(x-1)     = x&sup2;-4-x&sup2;+x     = (x&sup2;-x&sup2;)+x-4     = x-4     C&acirc;u 4:     x&sup2;-xy+x-y     = (x&sup2;+x)-(xy+y)     = x.(x+1)-y.(x+1)     = (x+1).(x-y)     C&acirc;u 5:     (x+y)&sup2;      = x&sup2;+2.x.y+y&sup2;     = x&sup2;+2xy+y&sup2;     C&acirc;u 6:     (x+y)&sup3;     = x&sup3;+3.x&sup2;.y+3.x.y&sup2;+y&sup3;     = x&sup3;+3x&sup2;y+3xy&sup2;+y&sup3;     @8A1

catlantuong · Answer

C&acirc;u 1:   x^2-xy+x-y   =(x^2-xy)+(x-y)   =x(x-y)+(x-y)   =(x-y)(x+1)   * Nh&oacute;m hạng tử   * Đặt nh&acirc;n tử chung   C&acirc;u 2:   (x-y)(x+y)   =x^2-y^2   * a^2-b^2=(a-b)(a+b)   C&acirc;u 3:   (x-2)(x+2)-x(x-1)   =x^2-4-x^2+x   =(x^2-x^2)+x-4   =x-4   * a^2-b^2=(a-b)(a+b)   C&acirc;u 4:   x^2-xy+x-y   =(x^2-xy)+(x-y)   =x(x-y)+(x-y)   =(x-y)(x+1)   * Nh&oacute;m hạng tử   * Đặt nh&acirc;n tử chung   C&acirc;u 5:   (x+y)^2   =x^2+2xy+y^2   * (a+b)^2=a^2+2ab+b^2   C&acirc;u 6:   (x+y)^3   =x^3+3x^2y+3xy^2+y^3   * (a+b)^3=a^3+3a^2b+3ab^2+b^3