# Null Cline

#### mt91

##### New member
I was wondering if anyone could help me clarify which null cline solutions are correct for this question I've got:

I've got two differential equations:

$du/dt =u(1-u)(a+u)-uv$
$dv/dt = buv-cv$

where a, b and c are constants.

I know to find the u null clines you set du/dt to 0.

$0=u(1-u)(a+u)-uv$

At this stage I know u=0 is a solution. However I'm not sure for the next null cline do I find it in terms of u or v?

So is it$v=-u^2 -au+u+a$
or

Any help would be great, cheers