Question

Solve : ( 3 - 5 root 7 ) ( 3 + root 7 )

Answer 1

Dear student
$$\begin{gathered} \left(3-5\sqrt{7}\right)\left(3+\sqrt{7}\right) \\ =9+3\sqrt{7}-15\sqrt{7}-35 \\ =-26-12\sqrt{7} \\ =-2\left(13+6\sqrt{7}\right) \end{gathered}$$
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