Question

If $2^a=3$ and $9^b=4$ then value of $\left(ab\right)$ is

• A. $1$
• B. $2$
• C. $3$
• D. $4$

Answer 1

Answer: (A)

$1$

$2^a=3$
$9^b=4$

$3^{2b}=2^2$

Taking square roots on boot sides.

$3^b=2$
Substituting $3=2^a$ in above:

$(2^a{)}^b=2⟹2^{ab}=2$

$⟹ab=1$