Toán Lớp 8: 4) ( ???? +2 ????)( ????^2 − 2???? ???? + 4????^2 )+ 16????^3 + 5 5) (???? − 5 )(???? + 8 ) − (???? + 4 )(???? − 1 ) 6) ???? ( 5???? − 3 ) − ????^2 ( ???? − 1 ) + ????

Question

Toán Lớp 8:  4) ( ???? +2 ????)( ????^2 − 2???? ???? + 4????^2 )+ 16????^3 + 5 5) (???? − 5 )(???? + 8 ) − (???? + 4 )(???? − 1 ) 6) ???? ( 5???? − 3 ) − ????^2 ( ???? − 1 ) + ???? ( ????^2 − 6???? ) − 10 + 3????

buianhtuan · Answer

Giải đáp +Lời giải và giải thích chi tiết:       4) (x+2y).(x&sup2;-2xy+4y&sup2;)+16y&sup3;+5     = (x+2y).[x&sup2;-x.2y+(2y)&sup2;]+16y&sup3;+5     = [x&sup3;+(2y)&sup3;]+16y&sup3;+5     = x&sup3;+8y&sup3;+16y&sup3;+5     = x&sup3;+24y&sup3;+5     5) (y-5).(y+8)-(y+4).(y-1)     = y&sup2;+3y-40-(y&sup2;+3y-4)     = y&sup2;+3y-40-y&sup2;-3y+4     = (y&sup2;-y&sup2;)+(3y-3y)+(4-40)     =-36     6) x.(5x-3)-x&sup2;.(x-1)+x.(x&sup2;-6x)-10+3x     = 5x&sup2;-3x-x&sup3;+x&sup2;+x&sup3;-6x&sup2;-10+3x     = (5x&sup2;+x&sup2;-6x&sup2;)+(3x-3x)+(x&sup3;-x&sup3;)-10     = -10       #anhnguyenff

tuminh25 · Answer

Giải đáp:       Lời giải và giải thích chi tiết:    4)     (x+2y).(x&sup2;-2xy+4y&sup2;)+16y&sup3;+5     = (x+2y).[x&sup2;-x.2y+(2y)&sup2;]+16y&sup3;+5     = [x&sup3;+(2y)&sup3;]+16y&sup3;+5     = x&sup3;+8y&sup3;+16y&sup3;+5     = x&sup3;+24y&sup3;+5     5)     (y-5).(y+8)-(y+4).(y-1)     = y&sup2;+3y-40-(y&sup2;+3y-4)     = y&sup2;+3y-40-y&sup2;-3y+4     = (y&sup2;-y&sup2;)+(3y-3y)+(4-40)     =-36     6)     x.(5x-3)-x&sup2;.(x-1)+x.(x&sup2;-6x)-10+3x     = 5x&sup2;-3x-x&sup3;+x&sup2;+x&sup3;-6x&sup2;-10+3x     = (5x&sup2;+x&sup2;-6x&sup2;)+(3x-3x)+(x&sup3;-x&sup3;)-10     = -10