The force exerted on the book by the table refers to the normal force `F_N` .
Note that a normal force is always perpendicular to the surface of contact. It is always directed upward, too.
Since the book is lying on a stationary table which means that the surface is horizontal and not moving up or down. So normal force `(F_N)` is equal to downward force which is the weight `(W)` of the book.
Moreover, since the book is at rest the forces acting on the book are `F_N` and `W` only.
Using Newton's Law,
`sum F = 0`
Since `F_N` is the upward force and `W` is the downard force, their signs differ.
`F_N - W=0`
Note that weight is the product of mass of an object and gravity. The value of gravity in earth is 9.8 m/s^2 .
`F_N = (1.75 kg)(9.8 m/s^2) = 17.15 N`
Hence, the force exerted on the book by the table is 17.15 N and is directed upward.