Solve with an array

So hello, the issue is that I have 4 arrays (Q0, Q1, Q2, Q3) and H, which is

H= Q0-Q1-Q2-Q3;

In these arrays (The Q ones) I have a variable, P3, which is a symbolic variable. So far we have Qn---> nxn sym

H= Q0(P3)-Q1(P3)-Q2(P3)-Q3(P3);

How can I know the value of P3 knowing that H is equal to 0?

Thank you very much.

[Juan Barrientos]

I forgot to tell, the Q variables depends also on a variable called x, which is a vector from 0 to 100.