\(\left(x+1\right)+\left(x+3\right)+...+\left(x+99\right)=5100\)
\(\Leftrightarrow50x+\frac{\left[\left(99-1\right):2+1\right]\left(99+1\right)}{2}=5100\)
\(\Leftrightarrow50x+2500=5100\)
\(\Leftrightarrow50x=2600\)
\(\Leftrightarrow x=52\)
Vậy ...
\(\left(x+1\right)+\left(x+3\right)+...+\left(x+99\right)=5100.\)
\(\Leftrightarrow x+1+x+3+...+x+99=5100.\)'
\(\Leftrightarrow\left(x+x+...+x\right)+\left(1+3+...+99\right)=5100\)
50 số hạng x 50 số hạng
\(\Leftrightarrow50x+\frac{\left(1+99\right)\cdot50}{2}=5100\)
\(\Leftrightarrow50x=5100-2500=2600\)
\(\Leftrightarrow x=52\)
Vậy x = 52
Học tốt nhé ^3^
nhanh lên các bạn
Ta có : ( x + 1 ) + ( x + 2 ) + ... + ( x + 99 ) = 5100
\(\Leftrightarrow\)x + 1 + x + 2 + ... + x + 99 = 5100
\(\Leftrightarrow\)99x + ( 1 + 2 + ... + 99 ) = 5100
\(\Rightarrow\)99x + [ ( 99 - 1 ) ÷ 1 + 1 ] . [ ( 99 + 1 ) ÷ 2 ] = 5100
\(\Rightarrow\)99x + 4950 = 5100
\(\Rightarrow\)99x = 5100 - 4950
\(\Rightarrow\)99x = 150
\(\Rightarrow\)x = 150 / 99
\(\Rightarrow\)x = 50 / 33
Vậy : x = 50 / 33
