Look at the previous formula, if

So a is greater than 0.

So the solution set of x=b/a is (1, +∞)= & gt；; a=b

∵(ax+b)/(x+2)>0 So (ax+b) * (x+2) > 0

So a(x+ 1)*(x+2)>0.

The solution set is (-∞, -2)∩(- 1,+∞).