Question

Pl solve it and do explain how to do these type of questions in which inside root over plus and minus signs are there and perfect squares are not there​

Answer 1

Step-by-step explanation:

Taking square on both sides we get

$13 - a\sqrt{10} = 8 + 5 + 2 \sqrt{40} \\ 13 - a \sqrt{10} = 13 + 2 \sqrt{4 \times 10} \\ - a \sqrt{10} = 2 \times 2 \sqrt{10} \\ - a = 4 \\ a = - 4$

Answer 2

Answer:

(C) -4

Step-by-step explanation:

In this type of question we can use squaring both sides and then compare LHS with RHS.

Refer attached image.