Recover plane constants from an intersection line

Planes p1,p2 are $2x-5y+3z=3$ and $3x+\lambda y+6z=\mu$.

(i) They intersect in l:$\mathbf r=(4,-2,-5)+s(-2,1,3)$, s real. Show λ=−12 and find μ.3 marks

Plane p3 is $5x+8y+tz=12$.

(ii) Using(i), find the exact t if p3 does not intersect l.2 marks

(iii) Plane p4 contains l and (1,−1,2). Find its Cartesian equation.3 marks