Question

i need help

Answer 1

\[\frac{ 12 }{ \sqrt{7}+2 }=\frac{ 12 }{ \sqrt{7}+2 }\times \frac{ \sqrt{7}-2 }{\sqrt{7}-2 }=\frac{ 12\left( \sqrt{7}-2\right) }{7-4 }\]
\[=\frac{ 12\left( \sqrt{7}-2 \right) }{ 3 }=4\left( \sqrt{7}-2 \right)\]