first arrange so that 1/x is on one side of the quation like so:Originally Posted bysorch

1/x = 4/5 - 4

Then simplify the right hand side like so:

1/x = 4/5 - 20/5

1/x = -16/5

Then invert both sides

x/1 = -5/16

or

x = -5/16,

plug it in to the equation to be sure of your answer:

4/5=1/(-5/16)+4

4/5=-16/5+4

4/5=-16/5+20/5

4/5=4/5