Question

Tìm x,biết:

2x+4x+6x+...+98x+100x=51.10²

Answer 1

\(2x+4x+6x+........+98x+100x=51.10^2\)

\(\Rightarrow x\left(2+4+6+.........+98+100\right)=51.100\)

\(\Rightarrow x.2550=5100\)

\(\Rightarrow x=5100:2550\)

\(\Rightarrow x=2\)

Vậy x = 2

Answer 2

\(2x+4x+6x+...+100x=51.10^2\)

\(\Rightarrow x\left(2+4+...+100\right)=5100\)

\(\Rightarrow x\left(\frac{\left[\left(100-2\right):2+1\right].\left(100+2\right)}{2}\right)=5100\)

\(\Rightarrow x\left(\frac{50.102}{2}\right)=5100\)

\(\Rightarrow\frac{5100x}{2}=5100\)

\(\Rightarrow5100x=5100.2\)

\(\Rightarrow x=2\)

Answer 3

2x + 4x + 6x + ...+ 98x + 100x = 51.10²

x.(2+4+6+...+98+100) = 51.100

\(x.\left[\left(2+100\right).50:2\right]=5100\)

x. 2550 = 5100

x = 5100 : 2550

x = 2