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

Toán Lớp 8: 4b : tính nhanh a) 85^2 – 15^2 b) 96^3 + 12 x 96^2 + 3 x 96 x 16 +64 c) 73^2 – 13^2 – 10^2 + 20 x 13 d) 96^3 + 86^3 / 182 – 96 x 86

Toán Lớp 8: 4b : tính nhanh
a) 85^2 – 15^2
b) 96^3 + 12 x 96^2 + 3 x 96 x 16 +64
c) 73^2 – 13^2 – 10^2 + 20 x 13
d) 96^3 + 86^3 / 182 – 96 x 86

Comments ( 2 )

  1. a,
    85^2-15^2
    =(85+15)(85-15)
    =100.70
    =7000
    b,
    96^3+12.96^2+3.96.16+64
    =96^3+3.96^2.4+3.96.4^2+4^3
    =(96+4)^3
    =100^3
    =1000000
    c,
    73^2-13^2-10^2+20.13
    =73^2-(13^2-2.13.10+10^2)
    =73^2-(13-10)^2
    =73^2-3^2
    =(73-3)(73+3)
    =70.76
    =5320
    d,
    (96^3+86^3)/182-96.86
    =((96+86)(96^2-96.86+86^2))/182-96.86
    =(182.(96^2-96.86+86^2))/182-96.86
    =96^2-96.86+86^2-96.86
    =96^2-2.96.86+86^2
    =(96-86)^2
    =10^2
    =100
     

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