Register Now

Login

Lost Password

Lost your password? Please enter your email address. You will receive a link and will create a new password via email.

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

Toán Lớp 8: Thực hiện phép tính b) ( -2×3 + y2 -7xy). (-4xy2 ) c)(x2 -2x+3). (x+4) d) ( 2×3 -3x -1). (5x-2)

Toán Lớp 8: Thực hiện phép tính
b) ( -2×3 + y2 -7xy). (-4xy2 ) c)(x2 -2x+3). (x+4)
d) ( 2×3 -3x -1). (5x-2)

Comments ( 2 )

  1. Giải đáp + Lời giải và giải thích chi tiết:
    b) ( -2x^3 + y^2 – 7xy). (- 4xy^2 )
    = 8x^4y^2 – 4xy^4 + 28x^2y^3
    c) (x^2 – 2x + 3). (x+4)
    = x^3 + 4x^2 – 2x^2 – 8x + 3x + 12
    = x^3 – 2x^2 – 5x + 12
    d) (2x^3 – 3x – 1). (5x – 2)
    = 10x^4 – 4x^3 – 15x^2 + 6x – 5x + 2
    = 10x^4 – 4x^3 – 15x^2 – x + 2

  2. ( -2x^3 + y^2 -7xy). (-4xy^2 )
    =-2x³.(-4xy²) + y².(-4xy²) – 7xy.(-4xy²)
    =8x^4 y² -4xy^4 + 28x²y³
    —–
    (x²-2x+3).(x+4)
    =x(x²-2x+3)+4(x²-2x+3)
    =x.x²-x.2x+x.3+4x²-2x.4+4.3
    =x³-2x²+3x+4x²-8x+12
    =x³+2x²-5x+12
    ——
    (2x³-3x-1)(5x-2)
    =5x(2x³-3x-1)-2(2x³-3x-1)
    =5x.2x³-5x.3x-5x.1-2.2x³-2.(-3x) -2.(-1)
    =10x^4 -15x²-5x-4x³+6x+2
    =10x^4 -4x³-15x²+x+2

Leave a reply

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