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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 8: thực hiện phép tính a 3x^2-5y + 5y-6xy x-2y x-2y b 6x + 3 — 6x^2-29x-4 x+4 4- x

Toán Lớp 8: thực hiện phép tính
a 3x^2-5y + 5y-6xy
x-2y x-2y

b 6x + 3 — 6x^2-29x-4
x+4 4- x x^2-16
c x-1 + 3x+1 + 2x
x +1 1-x^2 x-1
help hứa vote 5 *

Comments ( 1 )

  1. Giải đáp:
     
    Lời giải và giải thích chi tiết:
     a,[3x^2 -5y]/[x-2y]+[5y-6xy]/[x-2y]
    =[3x^2 -5y+5y-6xy]/[x-2y]
    =[3x^2 -6xy]/[x-2y]
    =[3x(x-2y)]/[x-2y]
    =3x
    b,[6x]/[x+4]+3/[4-x]-[-6x^2 -29x-4]/[x^2 -16]
    =[6x]/[x+4]-3/[x-4]+[6x^2 +29x+4]/[(x-4)(x+4)]
    =[6x(x-4)-3(x+4)+6x^2 +29x+4]/[(x-4)(x+4)]
    =[6x^2 -24x-3x-12+6x^2 +29x +4]/[(x-4)(x+4)]
    =[12x^2 +2x-8]/[(x-4)(x+4)]
    c,[x-1]/[x+1]+[3x+1]/[1-x^2]+[2x]/[x-1]
    =[x-1]/[x+1]-[3x+1]/[(x-1)(x+1)]+[2x]/[x-1]
    =[(x-1)(x-1)-(3x+1)+2x(x+1)]/[(x-1)(x+1)]
    =[x^2 -2x+1-3x-1+2x^2 +2x]/[(x-1)(x+1)]
    =[3x^2 -3x]/[(x-1)(x+1)]
    =[3x(x-1)]/[(x-1)(x+1)]
    =[3x]/[x+1]

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222-9+11+12:2*14+14 = ? ( )