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

Toán Lớp 8: Bài 1 : Tính a) (3x – 1).(4x + 9) b) (6x ³ – xy + 15).(2x ² – 4xy) Bài 2 : rút gọn a) x(x + 2) – x(2x ² – x + 1) b) (x – 1) (x + 5) –

Tháng Tám 23, 2022 Toán học 2 Comments 0 views

Toán Lớp 8: Bài 1 : Tính
a) (3x – 1).(4x + 9)
b) (6x ³ – xy + 15).(2x ² – 4xy)
Bài 2 : rút gọn
a) x(x + 2) – x(2x ² – x + 1)
b) (x – 1) (x + 5) – (2x – 1) (x – 6)
c) (xy – ) (3x ²y + y ²)

Comments ( 2 )

  1. huenthanh97
    huenthanh97
    23 Tháng Tám, 2022 at 10:39 sáng
    Reply
    Bài 1.
    a)
    $= 12x^2 + 27x – 4x-9$
    $=12x^2 +23x-9$
    b)
    $= 12x^5 – 24x^4y – 2x^3y + 4x^2y^2+30x^2-60xy$
    Bài 2
    a)
    $= x^2 + 2x-2x^3 +x^2 -x$
    $= 2x^2 +x-2x^3$
    b)
    $= x^2 +5x-x-5-(2x^2 -12x-x+6)$
    $= x^2 + 5x-x-5-2x^2 + 13x-6$
    $= -x^2+17x-11$
    c)
    $(xy-2)(3x^2y+y^2)$
    $= xy.3x^2y+xy.y^2 -2.3x^2y-2y^2$
    $= 3x^3y^2 +xy^3-6x^2y-2y^2$

    toan-lop-8-bai-1-tinh-a-3-1-4-9-b-6-y-15-2-4y-bai-2-rut-gon-a-2-2-1-b-1-5

  2. ngocle44
    ngocle44
    23 Tháng Tám, 2022 at 10:38 sáng
    Reply
    Giải đáp+Lời giải và giải thích chi tiết:
    $\text{Bài 1:}$
    a) (3x-1)(4x+9)
    =12x²+27x-4x-9
    =12x²+23x-9
    b) (6x³-xy+15)(2x²-4xy)
    =12x^5-24x^4y-2x³y+4x²y²+30x²-60xy
    $\text{Bài 2:}$
    a) x(x+2)-x(2x²-x+1)
    =x²+2x-2x³+x²-x
    =-2x³+2x²+x
    b) (x-1)(x+5)-(2x-1)(x-6)
    =x²+5x-x-5-(2x²-12x-x+6)
    =x²+5x-x-5-2x²+12x+x-6
    =-x²+17x-11
    c) (xy-2)(3x²y+y²)
    =3x³y²+xy³-6x²y-2y²
          Chúc bn hc tốt????
                $\text{#LinhSad}$ 

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

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