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

Toán Lớp 8: Bài 3. Thực hiện phép tính sau: a) 3y^2(2y – 1) + y – y(1 – y + y^2) – y^2 + y; b) 2x^2.a – a(1 + 2x^2) – a – x(x + a); c) 2p. p^2 –

Toán Lớp 8: Bài 3. Thực hiện phép tính sau:
a) 3y^2(2y – 1) + y – y(1 – y + y^2) – y^2 + y;
b) 2x^2.a – a(1 + 2x^2) – a – x(x + a);
c) 2p. p^2 -(p^3 – 1) + (p + 3). 2p^2 – 3p^5;
d) -a^2(3a – 5) + 4a(a^2 – a).
LÀM CHI TIẾT NHA KO ĐC LÀM TẮT

Comments ( 1 )

  1. a) 3y^2 ( 2y – 1 ) + y – y ( 1 – y + y^2 ) – y^2 + y
    = 6y^3 – 3y^2 + y – y + y^2 – y^3 – y^2 + y
    = ( 6y^3 – y^3 ) + ( – 3y^2 + y^2 – y^2 ) + ( y + y )
    = 5y^3 – 3y^2 + 2y
    b) 2x^2 . a – a ( 1 + 2x^2 ) – a – x ( x + a )
    = 2x^2a – a – 2x^2a – a – x^2 – xa
    = ( 2x^2a – 2x^2a ) + ( – a – a ) – x^2 – xa
    = – 2a – x^2 – xa
    c) 2p . p2 – ( p^3 – 1 ) + ( p + 3 ) . 2p^2 – 3p^5
    = 2p^3 – p^3 + 1 + 2p^3 + 6p^2 – 3p^5
    = – 3p^5 + ( 2p^3 – p^3 + 2p^3 ) + 6p^2 + 1
    = – 3p^5 +3p^3 + 6p^2 + 1
    d) – a^2 ( 3a – 5 ) + 4a ( a^2 – a )
    = -3a^3 + 5a^2 + 4a^3 – 4a^2
    = ( – 3a^3 + 4a^3 ) + ( 5a^2 – 4a^2 )
    = a^3 + a^2

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

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