How to exclude complex solutions to differential equation?

I have a probably rather easy-to-solve question. I am solving an equation but receive solutions in terms of complex numbers. However, I am not interested in complex solutions. Moreover, when inserting actual numeric value, the imaginary parts are extremely small, something like 10^(-14)i . This hints on lacking precision and I am happy to ignore these values in the numerical solutions. Yet, I cant wrap my head around the analytical solutions and how I can get rid of the imaginary parts there - how can I impose that all solutions must be real?

I define a triangular function:

triang[x_] := Piecewise[{{0, x <= 0},
{ x / p^2, 0 < x <= p},
{(2 p - x)/p^2, 2 p > x > p},
{0, x >= 2 p}}]

Equity := Integrate[y/ae * (x - ss) * triang[x], {x, ss, 2 p},
Assumptions -> ss <= 2 p && p > 0 && ss > 0]

Simplify[Equity, Assumptions -> ae > 0]

--> yields the three different cases, which will be solved individually depending on p and ss --> for simplicity, only the first case follows, as my questions are similar for the others

InvCase1 := (ss y)/ad + ((2 p - ss)^3 y)/(6 ae p^2)

Solve[InvCase1 == inv , ss]

This yields a really lengthy solution including complex parts :/ Any idea how I get only real solutions? All the variables are real and >=0. Thank you!