Discussion Forum



1)

If $\left(\frac{a}{b}\right)^{x-1}=\left(\frac{b}{a}\right)^{x-3}$, then the value of x is:


A) 1/2

B) 1

C) 2

D) 7/2

Answer:

Option C

Explanation:

$\left(\frac{a}{b}\right)^{x-1}=\left(\frac{b}{a}\right)^{x-3}$ $ \Leftrightarrow\left(\frac{a}{b}\right)^{x-1}=\left(\frac{a}{b}\right)^{-\left(x-3\right)}$ $=\left(\frac{a}{b}\right)^{3-x}$ $\Leftrightarrow x-1 =3-x$ $\Leftrightarrow 2x=4$ $\Leftrightarrow x=2$