Question

if $\sqrt{13 - a \sqrt{10} } = \sqrt{8} + \sqrt{5}$ then a =?

Answer 1

√( 13 -a√10) = √8 + √5

take square both sides ,

13 -a√10 = 13 + 2√40

-a√10 = 2√40

-a√10 =4√10

a = -4 ( answer)