Toán Lớp 8: A = 2xyz.(-5x^2y^3) B = (-3/4x^5y^4).(xy^2).(-8/9x^2y^5) C = x^3.9-5/4x^2y).(2/5x^3y^4)^3

Question

Toán Lớp 8:  A = 2xyz.(-5x^2y^3) B = (-3/4x^5y^4).(xy^2).(-8/9x^2y^5) C = x^3.9-5/4x^2y).(2/5x^3y^4)^3

tuminh25 · Answer

Giải đáp+Lời giải và giải thích chi tiết:    A = 2xyz . (-5x&sup2;y&sup3;)    = [2.(-5)].(x.x&sup2;).(y.y&sup3;).z   = -10x&sup3;y^4z   B = (-3/4x^5y^4).(xy&sup2;).(-8/9x&sup2;y^5)   = [(-3/4).(-8/9)].(x^5.x.x&sup2;).(y^4.y&sup2;.y^5)   = 2/3x^8y^11   C = (x&sup3; . 9 - 5/4x&sup2;y).(2/5x&sup3;y^4)&sup3;   = (9x&sup3; - 5/4x&sup2;y).(2/5x&sup3;y^4)&sup3;   = (9x&sup3; - 5/4x&sup2;y) . (8/125x^27y^12)   = 72/125x^30y^12 - 2/25x^29y^13

minhtuquynh · Answer

Giải đáp:    A = 2xyz.(-5x^2 y^3)     = [2.(-5)] . (x.x^2).(y.y^3).z     = -10x^3 y^4 z     B = (-3/4x^5 y^4).(xy^2).(-8/9x^2 y^5)     = [(-3/4).(-8/9)].(x^5 .x.x^2).(y^4 .y^2.y^5)     = 2/3 x^8 y^11     C = (x^3.9-5/4x^2 y).(2/5x^3 y^4)^3     = (9x^3 - 5/4 x^2 y).[(2/5)^3 .(x^3)^3 . (y^4)^3]     = (9x^3 - 5/4 x^2 y). (8/125 . x^9 . y^12)     = 9x^3 . 8/125 .x^9 .y^12 + (-5/4 x^2 y). 8/125 . x^9 . y^12     = (9. 8/125).(x^3 . x^9).y^12 + (-5/4 . 8/125).(x^2 . x^9) .(y . y^12)     = 72/125 x^12 y^12 - 2/25 x^11 y^13