hello, I am studying for my exams and I came across a question that is really giving me trouble:

The planes: 2x + 3y + z = 2 and 5x - 2y + 2z = -4 are given. Find the scalar equation of the plane that contains the line of intersection of plane 1 and 2 and that passes through the origin.

I tried to use Ax + By + Cz + D + k(A2x + B2y + C2z + d2) = 0 but it didn't really seem to work out.

for quick reference:

scalar equation = ax + by + cz + d = 0

the answer at the back of the book is 9x + 4y + 4z = 0 but it might be wrong.

I will really appreciate some help.

Thanks a lot!!!