The notation is ambiguous.

If you meant `4/(5x)+4/5=16/(x+12)` then we can multiply both sides of the equation by `5x(x+12)` which is the least common denominator. Then we get:

`4(x+12)+4x(x+12)=16(5x)`

`4x+48+4x^2+48x=80x`

`4x^2-28x+48=0`

`4(x^2-7x+12)=0`

`4(x-4)(x-3)=0`

**The solutions would be x=4 or x=3.**