B. [tex] \sqrt{x} + \sqrt{x - 1} [/tex] ✅
[tex]\large\mathfrak{{\pmb{\underline{\red{Step-by-step\:explanation}}{\orange{:}}}}}[/tex]
[tex] \frac{1}{ \sqrt{x} - \sqrt{x - 1} } \\ \\= \frac{1}{ \sqrt{x} - \sqrt{x - 1} } \times \frac{ \sqrt{x} + \sqrt{x - 1} }{ \sqrt{x} + \sqrt{x - 1} } \\ \\ = \frac{ \sqrt{x} + \sqrt{x - 1} }{ ({ \sqrt{x} })^{2} - { (\sqrt{x - 1} })^{2} } \\\\ [∵(a + b)(a - b) = {a}^{2} - {b}^{2} ] \\ \\= \frac{ \sqrt{x} + \sqrt{x - 1} }{x - (x - 1)} \\ \\= \frac{ \sqrt{x} + \sqrt{x - 1} }{ x - x + 1} \\ \\= \sqrt{x} + \sqrt{x - 1} [/tex]
[tex]\bold{ \green{ \star{ \orange{Mystique35}}}}⋆[/tex]
