find the value of x.

I'm assuming this is

2x - 8           3x

-------      =   ----                       cross-multiply

  4                 5

5(2x - 8)  = 4 * (3x)       simplify

10x - 40   = 12x          subtract 10x from both sides

-40   = 2x      divide both sides by 2

-20   = x