Hello I was wondering if you could help with this question:

Find any intersections between the planes:

i) $\displaystyle 2x+y-z=0$

and

ii) $\displaystyle z=x^2+y^2+x-3y+15$

Oh and equation (i) and

iii) $\displaystyle (x,y,z) = (3,-5,1)s + (3,0,20)$

Any help at all would be much appreciated. I'm pretty sure you have to sub these equations in to each other, except when I try and do these, I get something like -14=0 and also complex numbers, these are wrong right?