PLEASE HELP MATHS PROBLEM!!!

Step-by-step explanation:
[tex] \frac{5}{1 - \sqrt{7} } \\ multiply \: both \: by \: (1 + \sqrt{7) } \\ \frac{5(1 + \sqrt{7)} }{(1 - \sqrt{7})(1 + \sqrt{7)} } \\ = \frac{5(1 + \sqrt{7)}}{1 - { \sqrt{7} }^{2} } \\ = \frac{5(1 + \sqrt{7)} }{1 - 7} \\ = \frac{5(1 + \sqrt{7)} }{ - 6} \\ = \frac { - 5}{ \: 6} \frac{(1 + \sqrt{7}) }{} [/tex]