-5x+4=-2
When you say "substitution", that usually means that you want to plug in a particular value of x. On the other hand, one can solve this equation for x, which is done below (just in case that's what you meant):
-5x + 4 = -2
-5x = -6
x = 6/5
The answer (if wanting to solve) is x = 6/5.