Answer :

Let's solve the given problem step-by-step.

We start with the given equation:

[tex]\[ \sqrt{7 + \sqrt{48}} = m + \sqrt{n} \][/tex]

First, simplify the expression inside the square root. Notice that:

[tex]\[ \sqrt{48} = \sqrt{16 \cdot 3} = \sqrt{16} \cdot \sqrt{3} = 4\sqrt{3} \][/tex]

So the equation now becomes:

[tex]\[ \sqrt{7 + 4\sqrt{3}} = m + \sqrt{n} \][/tex]

Assume [tex]\( m = 2 \)[/tex] and [tex]\( n = 3 \)[/tex]. We need to verify this assumption by seeing if squaring both sides gives us a correct equality. Thus,

[tex]\[ (m + \sqrt{n})^2 = (2 + \sqrt{3})^2 \][/tex]

Calculate the square on the right-hand side:

[tex]\[ (2 + \sqrt{3})^2 = 2^2 + 2 \cdot 2 \cdot \sqrt{3} + (\sqrt{3})^2 \][/tex]

Breaking it down, we get:

[tex]\[ 4 + 4\sqrt{3} + 3 = 7 + 4\sqrt{3} \][/tex]

So, our assumptions of [tex]\( m = 2 \)[/tex] and [tex]\( n = 3 \)[/tex] are correct because the expressions match:

[tex]\[ \sqrt{7 + 4\sqrt{3}} = 2 + \sqrt{3} \][/tex]

Now, we need to find [tex]\( m^2 + n^2 \)[/tex].

Calculate [tex]\( m^2 \)[/tex]:

[tex]\[ m^2 = 2^2 = 4 \][/tex]

Calculate [tex]\( n^2 \)[/tex]:

[tex]\[ n^2 = 3^2 = 9 \][/tex]

Then, add these results together:

[tex]\[ m^2 + n^2 = 4 + 9 = 13 \][/tex]

Thus, the value of [tex]\( m^2 + n^2 \)[/tex] is:

[tex]\[ \boxed{13} \][/tex]