Question

What is 3^-1 + 4^-1 ?

Answer 1

`(7)/(12)` or 0.583

Answer 2

The answer is

`(7)/(12)`

Explanation:

Using the rules of indices

`{x}^( - y)`

can be written as

`\frac{1}{ {x}^(y) }`

So

`{3}^( - 1)`

can be written as

`(1)/(3)`

and

`{4}^( - 1)`

as

`(1)/(4)`

Add them

That's

`(1)/(3) + (1)/(4)`

Find the LCM

The LCM of 3 and 4 is 12

We have the final answer as

`(1)/(3) + (1)/(4) = (4 + 3)/(12) \\ = (7)/(12)`

Hope this helps you.