Answer
(a) Since the dot product gives scalar then the expression
$$(\mathbf{u} \cdot \mathbf{v})-\mathbf{v}$$
is meaningless, that is, one can not subtract a vector from a scalar.
(b Since the dot product gives scalar then the expression
$$\mathbf{v}+(\mathbf{u} \cdot \mathbf{v})$$
is meaningless, that is, one can not add a vector to a scalar.
Work Step by Step
(a) Since the dot product gives scalar then the expression
$$(\mathbf{u} \cdot \mathbf{v})-\mathbf{v}$$
is meaningless, that is, one can not subtract a vector from a scalar.
(b Since the dot product gives scalar then the expression
$$\mathbf{v}+(\mathbf{u} \cdot \mathbf{v})$$
is meaningless, that is, one can not add a vector to a scalar.
