Answer :

Let's simplify the given expression step-by-step:
[tex]\[ \frac{\sqrt{3} + \sqrt{7}}{\sqrt{27} + \sqrt{63} - \sqrt{28} - \sqrt{48}} \][/tex]

First, let's break down the terms in the denominator:

1. [tex]\(\sqrt{27}\)[/tex]:
[tex]\[ \sqrt{27} = \sqrt{9 \times 3} = 3 \sqrt{3} \][/tex]

2. [tex]\(\sqrt{63}\)[/tex]:
[tex]\[ \sqrt{63} = \sqrt{9 \times 7} = 3 \sqrt{7} \][/tex]

3. [tex]\(\sqrt{28}\)[/tex]:
[tex]\[ \sqrt{28} = \sqrt{4 \times 7} = 2 \sqrt{7} \][/tex]

4. [tex]\(\sqrt{48}\)[/tex]:
[tex]\[ \sqrt{48} = \sqrt{16 \times 3} = 4 \sqrt{3} \][/tex]

Now, substituting these simplified forms back into the denominator gives us:
[tex]\[ \sqrt{27} + \sqrt{63} - \sqrt{28} - \sqrt{48} = 3\sqrt{3} + 3\sqrt{7} - 2\sqrt{7} - 4\sqrt{3} \][/tex]

Next, let's combine the like terms in the denominator:
[tex]\[ 3\sqrt{3} - 4\sqrt{3} + 3\sqrt{7} - 2\sqrt{7} \][/tex]

This simplifies to:
[tex]\[ (3 - 4)\sqrt{3} + (3 - 2)\sqrt{7} = -\sqrt{3} + \sqrt{7} \][/tex]

So our simplified expression is:
[tex]\[ \frac{\sqrt{3} + \sqrt{7}}{-\sqrt{3} + \sqrt{7}} \][/tex]

Finally, we can evaluate the numerical value of this expression. Given the resulting values:
- The numerator [tex]\(\sqrt{3} + \sqrt{7} \approx 4.3778\)[/tex]
- The denominator [tex]\(-\sqrt{3} + \sqrt{7} \approx 0.9137\)[/tex]

Thus, the expression evaluates to:
[tex]\[ \frac{4.3778}{0.9137} \approx 4.7913 \][/tex]

So, the fraction [tex]\(\frac{\sqrt{3} + \sqrt{7}}{\sqrt{27} + \sqrt{63} - \sqrt{28} - \sqrt{48}}\)[/tex] simplifies to approximately [tex]\(4.7913\)[/tex].