Hello Stephen!
Thanks, I edited my question.
No, I know it's possible to define the linear transformation I'm asking what should be the linear transformation and how can I get there :)
Admit that V is a linear space about \mathbb{R} and that U and W are subspaces of V. Suppose that S: U \rightarrow Y and T: W \rightarrow Y are two linear transformations that satisfy the property:
(\forall x \in U \cap W) S(x)=T(x)
Define a linear transformation F: U+W \rightarrow Y that...