Question

please tell correct answer I will mark you as a brainlist​

Answer 1

Answer:

(b) a=123,b= -55 is correct.

Step by step explanation:

Given:

$\frac{7 - 3 \sqrt{5} }{9 + 4 \sqrt{5} } = a + b \sqrt{5}$

On Rationalizing :

$\frac{7 - 3 \sqrt{5} }{9 + 4 \sqrt{5} } \times \frac{9 - 4 \sqrt{5} }{9 - 4 \sqrt{5} } = a + b \sqrt{5}$

$\frac{63 - 28 \sqrt{5} - 27 \sqrt{5} + 60 }{ {9}^{2} - { (4 \sqrt{5} )}^{2} } = a + b \sqrt{5}$

$\frac{123 - 55 \sqrt{5} }{81 - 80} = a + b \sqrt{5}$

$123 - 55 \sqrt{5} = a + b \sqrt{5}$

On comparing both sides:

a= 123

b= -55