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

Toán Lớp 8: a) x ² – y ² – 2x + 2y b) 2x+2y – x ² – xy c) x ² – 25 + y ² + 2xy d) 4x ² – 25 + (2x+7)(5-2x) e) x ³ + x ²y – 4x – 4y f) 3(x+4) – x ²

Toán Lớp 8: a) x ² – y ² – 2x + 2y
b) 2x+2y – x ² – xy
c) x ² – 25 + y ² + 2xy
d) 4x ² – 25 + (2x+7)(5-2x)
e) x ³ + x ²y – 4x – 4y
f) 3(x+4) – x ² -4x
Chi tiết và nhanh giúp tớ nhé!

Comments ( 1 )

  1. Giải đáp + Lời giải và giải thích chi tiết !
    a)
    x^2-y^2-2x+2y
    = (x^2-y^2)-(2x-2y)
    = (x-y)(x+y)-2(x-y)
    = (x-y)(x+y-2)
    b)
    2x+2y-x^2-xy
    = (2x+2y)-(x^2+xy)
    = 2(x+y)-x(x+y)
    = (2-x)(x+y)
    c)
    x^2-25+y^2+2xy
    = (x^2+2xy+y^2)-25
    = (x+y)^2-5^2
    = (x+y-5)(x+y+5)
    d)
    4x^2-25+(2x+7)(5-2x)
    = (4x^2-25)+(2x+7)(5-2x)
    = (2x-5)(2x+5)-(2x-5)(2x+7)
    = (2x-5)(2x+5-2x-7)
    = -2(2x-5)
    e)
    x^3+x^2y-4x-4y
    = (x^3+x^2y)-(4x+4y)
    = x^2(x+y)-4(x+y)
    = (x^2-4)(x+y)
    = (x-2)(x+2)(x+y)
    f)
    3(x+4)-x^2-4x
    = 3(x+4)-(x^2+4x)
    = 3(x+4)-x(x+4)
    = (3-x)(x+4)
     

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