The three planes 4y + 6z = 5,2x + 3y + 5z = 5 and 6x + 5y + 9z= 0

Plane passing through the line of intersection of planes  4y + 6z = 5,2x + 3y + 5z = 5 (4y+6z−5)+λ(2x+3y+5z−5)=0or  2λx+(3λ+4)y+(5λ+6)z−5λ−5=0Clearly, for λ=3, w€ get the plane 6x + 5y + 9z =10. Hence, the given three planes have common line of intersection.