Tick (✓) the correct answer

Question:

Tick (✓) the correct answer

The value of $x$ for which $\left(\frac{7}{12}\right)^{-4} \times\left(\frac{7}{12}\right)^{3 x}=\left(\frac{7}{12}\right)^{5}$, is

(a) $-1$

(b) 1

(c) 2

(d) 3

Solution:

(d) 3

$\left(\frac{7}{12}\right)^{-4} \times\left(\frac{7}{12}\right)^{3 x}=\left(\frac{7}{12}\right)^{5}$

$\Rightarrow\left(\frac{7}{12}\right)^{-4+3 x}=\left(\frac{7}{12}\right)^{5}$

$\Rightarrow 3 x-4=5$

$3 x=9$

or $x=\frac{9}{3}=3$

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