Toán Lớp 9: A. (X+1)+(x+2)+(x+3)+….+(x+10)=2077
B.(2x+1)^3
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Toán Lớp 9: A. (X+1)+(x+2)+(x+3)+….+(x+10)=2077
B.(2x+1)^3
Comments ( 2 )
a)\left( {x + 1} \right) + \left( {x + 2} \right) + \left( {x + 3} \right) + … + \left( {x + 10} \right) = 2077\\
\Leftrightarrow x + x + … + x + 1 + 2 + 3 + .. + 10 = 2077\\
\Leftrightarrow 10.x + \dfrac{{\left( {10 + 1} \right).10}}{2} = 2077\\
\Leftrightarrow 10.x + 55 = 2077\\
\Leftrightarrow 10x = 2022\\
\Leftrightarrow x = 202,2\\
Vậy\,x = 202,2\\
b){\left( {2x + 1} \right)^3} = ??
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