Question

If 2ˣ⁻¹=1/8 then the value of x is

a)0 b)2 c)-2​

Answer 1

Answer:

2ˣ⁻¹=1/8

2ˣ⁻¹=(1/2)³

(1/2)¹⁻ˣ = (1/2)³

Since bases are same, powers can be equated

so,

1-x = 3

1-3 = x

-2 = x

c) Ans.

Hope this helps ☺️

Answer 2

Answer:

c) -2

Step-by-step explanation:

$\frac{1}{8} = \frac{1}{ {2}^{3} } = {2}^{ - 3} \\ given \: {2}^{x - 1} = \frac{1}{8} = {2}^{ - 3}$

comparing the powers,

x - 1 = -3

So x = -2