Question

A = √7 + √c and b = √63 + √d where c and d are positive integers.

Answer 1

Answer:

$\displaystyle a:b=\frac{1}{3}$

Step-by-step explanation:

Ratios

We are given the following relations:

$a=\sqrt{7}+\sqrt{c}\qquad \qquad[1]$

$b=\sqrt{63}+\sqrt{d}\qquad \qquad[2]$

$\displaystyle \frac{c}{d}=\frac{1}{9} \qquad \qquad [3]$

From [3]:

$9c=d$

Replacing into [2]:

$b=\sqrt{63}+\sqrt{9c}$

We can express 63=9*7:

$b=\sqrt{9*7}+\sqrt{9c}$

Taking the square root of 9:

$b=3\sqrt{7}+3\sqrt{c}$

Factoring:

$b=3(\sqrt{7}+\sqrt{c})$

Find the ration a:b:

$\displaystyle a:b=\frac{\sqrt{7}+\sqrt{c}}{3(\sqrt{7}+\sqrt{c})}$

Simplifying:

$\boxed{a:b=\frac{1}{3}}$