The first problem (marked with "গ") asks to show something, given $a = 2 + \sqrt{3}$ and $a+b = 4$. However, the exact equation that needs to be shown is not recognizable. The second problem (marked with "ক") asks to factor the expression $y^2 - 9z^2 + 16y + 64$.

1. Problem Description

The first problem (marked with "গ") asks to show something, given $a = 2 + \sqrt{3}$ and $a+b = 4$. However, the exact equation that needs to be shown is not recognizable. The second problem (marked with "ক") asks to factor the expression $y^2 - 9z^2 + 16y + 64$.

2. Solution Steps

Let's focus on the second problem (marked as "ক"). We want to factor the expression $y^2 - 9z^2 + 16y + 64$. We can rewrite the expression as:

$y^2 + 16y + 64 - 9z^2$

Notice that $y^2 + 16y + 64$ is a perfect square:

$y^2 + 16y + 64 = y^2 + 2(8)y + 8^2 = (y+8)^2$

So we can rewrite the expression as:

$(y+8)^2 - 9z^2 = (y+8)^2 - (3z)^2$

This is a difference of squares, which can be factored as:

$A^2 - B^2 = (A+B)(A-B)$

In this case, $A = y+8$ and $B = 3z$. Therefore:

$(y+8)^2 - (3z)^2 = (y+8+3z)(y+8-3z)$

3. Final Answer

The factored expression is $(y+8+3z)(y+8-3z)$.