Answer :

Certainly! Let's solve the problem step-by-step:

Given the equation:

[tex]\[ \frac{2+\sqrt{3}}{2-\sqrt{3}} = 7 - a \sqrt{3} \][/tex]

We need to find the value of \( a \) that satisfies this equation.

First, we rationalize the left-hand side by multiplying both the numerator and the denominator by the conjugate of the denominator \( 2 + \sqrt{3} \):

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

Next, we simplify the numerator and the denominator:

For the numerator:
[tex]\[ (2+\sqrt{3})(2+\sqrt{3}) = 2^2 + 2\cdot 2\cdot\sqrt{3} + (\sqrt{3})^2 = 4 + 4\sqrt{3} + 3 = 7 + 4\sqrt{3} \][/tex]

For the denominator:
[tex]\[ (2-\sqrt{3})(2+\sqrt{3}) = 2^2 - (\sqrt{3})^2 = 4 - 3 = 1 \][/tex]

Putting it all together, we get:
[tex]\[ \frac{7 + 4\sqrt{3}}{1} = 7 + 4\sqrt{3} \][/tex]

So, our equation now reads:
[tex]\[ 7 + 4\sqrt{3} = 7 - a\sqrt{3} \][/tex]

To find \( a \), we equate the terms involving \(\sqrt{3}\):

[tex]\[ 4\sqrt{3} = -a\sqrt{3} \][/tex]

Dividing both sides by \(\sqrt{3}\), we obtain:
[tex]\[ 4 = -a \][/tex]

Thus, solving for \( a \):
[tex]\[ a = -4 \][/tex]

Therefore, the value of [tex]\( a \)[/tex] is [tex]\( \boxed{-4} \)[/tex].