Solve equation (1)/(4) + (1)/(5) = (1)/(t)

Question

Solve equation
`(1)/(4) + (1)/(5) = (1)/(t)`

Answer 1

`(1)/(4) + (1)/(5) = (1)/(t) \\ (1 * 5)/(4 * 5) + (1 * 4)/(5 * 4) = (1)/(t) \\ (5)/(20) + (4)/(20) = (1)/(t) \\ (9)/(20) = (1)/(t)`

I WILL USE CROSS MULTIPLICATION

`t(9) = 20 \\ 9t = 20 \\ (9t)/(9) = (20)/(9) \\ t = (20)/(9)`

GOODLUCK.