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

Toán Lớp 8: 1/ Tính a)(????+4)^2 b)(3????−1)^2 c)(2????+5)^2 d)(3????−4????)^2

Toán Lớp 8: 1/ Tính a)(????+4)^2
b)(3????−1)^2
c)(2????+5)^2
d)(3????−4????)^2

Comments ( 2 )

  1. Giải đáp + Lời giải và giải thích chi tiết:
    a) (x + 4)^2 = x^2 + 2.x.4 + 4^2 = x^2 + 8x + 16
    b) (3x – 1)^2 = (3x)^2 – 2.3x.1 + 1^2 = 9x^2 – 6x + 1
    c) (2x + 5)^2 = (2x)^2 + 2.2x.5 + 5^2 = 4x^2 + 20x + 25
    d) (3a – 4b)^2 = (3a)^2 – 2.3a.4b + (4b)^2 = 9a^2 – 24ab + 16b^2

  2. a,
    (x+4)^2
    =x^2+2.x.4+4^2
    =x^2+8x+16
    b,
    (3x-1)^2
    =(3x)^2-2.3x.1+1^2
    =9x^2-6x+1
    c,
    (2x+5)^2
    =(2x)^2+2.2x.5+5^2
    =4x^2+20x+25
    d,
    (3a-4b)^2
    =(3a)^2-2.3a.4b+(4b)^2
    =9a^2-24ab+16b^2

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