Find the equations of the lines of greatest slope and least slope on the plane $3x-4y+5z-5=0$ drawn through the point $(1,2,2)$ given that the plane $4x-5y+6z-6=0$ is horizontal.
I do not need the solution of the problem rather I am unable to understand the following
What is meant by lines of greatest slope and least slope on the plane? Please explain in details, if possible, graphically.
Why the plane $4x-5y+6z-6=0$ is assumed as horizontal?
I shall be very happy if someone be kind enough to help me by providing the above information so that I can understand the problem and solve.
EDIT:
I understand about lines of greatest slope. Please help me to solve lines of least slope.