[tex]\[\begin{array}{l}\sqrt {5x + 1} - 10 = 6\\\\\sqrt {5x + 1} = 6 + 10\\\\\sqrt {5x + 1} = 16\\\\5x + 1 = {16^2}\\\\5x + 1 = 256\\\\5x = 256 - 1\\\\5x = 255\\\\x = 51\end{array}\][/tex]