Tìm x biết: x + 4x + 7x + 10x + ... + 58x = 595.

x + 4x + 7x + 10x + ... + 58x = 595

⇔ x(1 + 4 + 7 + 10 + … + 58) = 595

⇔ \[x.\frac{{\left( {1 + 58} \right).\left[ {\frac{{\left( {58 - 1} \right)}}{3} + 1} \right]}}{2} = 595\]

⇔ 590x = 595

⇔ \(x = \frac{{595}}{{590}}\)

⇔ \(x = \frac{{119}}{{118}}\).