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

Toán Lớp 8: Phân tích đa thức thành nhân tử a, 2.(x+5) – x2 – 5x b, x4 + 2×3 + x2 c, x3 – x + y3 – y d, x2 – x – y2 – y

Toán Lớp 8: Phân tích đa thức thành nhân tử
a, 2.(x+5) – x2 – 5x
b, x4 + 2×3 + x2
c, x3 – x + y3 – y
d, x2 – x – y2 – y

Comments ( 2 )

  1. a, 2(x+5) – x^2 – 5x
    = 2(x+5) + (-x^2 – 5x)
    = 2(x+5) – x( x+5)
    = (x+5)(2-x)
    b, x^4 + 2x^3 +x^2
    = x^4 + x^3 + x^3 + x^2
    = x^3 ( x+1) + x^2 (x+1)
    =(x+1)(x^3 + x^2 )
    =x^2 (x+1)(x+1)
    =x^2 (x+1)^2
    c, x^3 – x+ y^3 -y
    =(x^3 + y^3 ) + (-x-y)
    =(x+y)(x^2 – xy + y^2 ) – (x+y)
    =(x+y)(x^2 – xy + y^2 – 1)
    d, x^2 – x – y^2 -y
    = (x^2 – y^2 ) + (-x-y)
    =(x-y)(x+y) – (x+y)
    =(x+y)(x+y-1)
     

  2. Giải đáp+Lời giải và giải thích chi tiết:
    a) 2.(x+5) – x^2 – 5x
    =2.(x+5)-(x^2 + 5x)
    =2.(x+5) – x.(x+5)
    =(2-x)(x+5)
    b)x^4 + 2x^3 + x^2
    =x^2.(x^2+2x+1)
    =x^2.(x+1)^2
    c) x^3 – x + y^3 – y
    =(x^3+y^3)-(x+y)
    =(x+y).(x^2 – xy + y^2)-(x+y)
    =(x+y)(x^2 – xy + y^2-1)
    d)x^2 – x – y^2 – y
    =(x^2 – y^2) – (x+y)
    =(x-y).(x+y)-(x+y)
    =(x+y).(x-y-1)

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