Question 77

If $$2^{2n - 1} = \frac{1}{8^{n - 3}}$$, then $$2^{n - 2} =$$

Solution

Given,  $$2^{2n-1}=\frac{1}{8^{n-3}}$$

$$\Rightarrow$$  $$2^{2n-1}=\frac{1}{2^{3\left(n-3\right)}}$$

$$\Rightarrow$$  $$2^{2n-1}=2^{-3\left(n-3\right)}$$

As bases are equal, equating powers

$$2n-1=-3\left(n-3\right)$$

$$\Rightarrow$$  $$2n-1=-3n+9$$

$$\Rightarrow$$  $$5n=10$$

$$\Rightarrow$$  $$n=2$$

$$\therefore\ $$ $$2^{n-2}=2^{2-2}=2^0=1$$


Create a FREE account and get:

  • Download Maths Shortcuts PDF
  • Get 300+ previous papers with solutions PDF
  • 500+ Online Tests for Free

cracku

Boost your Prep!

Download App