Toán Lớp 8: a) x^3.( 2x^2-x-1/3) b) 4x^3-3x^2y+2xy^3).-(1/2x^2y) c) (x-2y) (5x+7xy^2) d) (1/3xy-2) x^3-6y

Question

Toán Lớp 8:  a) x^3.( 2x^2-x-1/3) b) 4x^3-3x^2y+2xy^3).-(1/2x^2y) c) (x-2y) (5x+7xy^2) d) (1/3xy-2) x^3-6y

tuyetnhungthu · Answer

Giải đáp:    Ph&iacute;a dưới   Lời giải và giải thích chi tiết:    a)x^3(2x^2-x-1/3)   =2x^5-x^4-1/3 x^3   b) (4x^3-3x^2y+2xy^3)(-1/2x^2y)   =-2x^5y-3/2 x^4y^2-x^3y^4   c) (x-2y)(5x+7xy^2)   =5x^2+7x^2y^2-10xy-14xy^3   d) (1/3xy-2)(x^3-6y)   =1/3x^4y-2xy^2-2x^3+12y

mocmien87 · Answer

#Applesff         ~Bạn tham khảo~:        a) x&sup3;.(2x&sup2;-x-1/3)     = x&sup3;.2x&sup2;-x&sup3;.x-x&sup3;.1/3     = 2x^5-x^4-1/3x&sup3;     b) (4x&sup3;-3x&sup2;y+2xy&sup3;).(-1/2x&sup2;y)     = 4x&sup3;.(-1/2x&sup2;y)+(-3x&sup2;y).(-1/2x&sup2;y)+ 2xy&sup3;.(-1/2x&sup2;y)     = -2x^5y+3/2x^4y&sup2;-x&sup3;y^4     c) (x-2y).(5x+7xy&sup2;)     = x.(5x+7xy&sup2;)-2y.(5x+7xy&sup2;)     = 5x&sup2;+7x&sup2;y&sup2;-10xy-14xy&sup3;     d) (1/3xy-2).x&sup3;-6y     = x&sup3;.(1/3xy-2)-6y.(1/3xy-2)     = 1/3x^4y-2x&sup3;-2xy&sup2;+12y       Ch&uacute;c bạn hc tốt!