Question

find a and b if
$\frac{7 + 3 \sqrt{5} }{2 + \sqrt{5} } - \frac{7 - 3 \sqrt{5} }{2 - \sqrt{5} } = a + b \sqrt{5}$

Answer 1

the answer is 2√5
use the identity (a+b)(a-b) to rationalize the denominators and make them equal