Indices

[delicate cipher]

How?

I got a brain fart looking at this

[compact ingot]

Well, x^(-1) = 1/x. So, in each one, bring the fractions under the common denominator.
For example, (a).
4^(-1) + 3^(-1) = 1/4 + 1/3 = (3 + 4)/12 = 7/12

[delicate cipher]

Thanks!

[native dragon]

@delicate cipher has given 1 rep to @compact ingot

[delicate cipher]

Wait, why 3+4/12?

Wait nevermind

[compact ingot]

(3 + 4)/12, not 3 + 4/12.

[delicate cipher]

My bad

@compact ingot

Sorry for ping

But one last question

[compact ingot]

Start by converting the fractions on the left to ordinary fractions.