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

Toán Lớp 7: cho C=1978.(1979^9+1979^8+…+1979^2+1980)+1.tính C

Toán Lớp 7: cho C=1978.(1979^9+1979^8+…+1979^2+1980)+1.tính C

Comments ( 1 )

  1. Giải đáp+Lời giải và giải thích chi tiết:
    $C=1987(1979^{9}+1979^{8}+…+1979^{2}+1980)+1$
    $=(1979-1)(1979^{9}+1979^{8}+…+1979^{2}+1979+1)+1$
    $=1979(1979^{10}+1979^{9}+…+1979^2+1979+1)-1(1979^{10}+1979^{9}+…+1979^2+1979+1)+1$
    $=(1979^{10}+1979^{9}+…+1979^{3}+1979^{2}+1979)-(1979^{9}+1979^{8}+1979^{2}+1979+1)+1$
    $=1979^{10}-1+1$
    $=1979^{10}$
    Vậy C= $1979^{10}$
     

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