Answer:
No, it isn't.
Step-by-step explanation:
We have [tex]V=IR^{2}[/tex] and let [tex]H[/tex] be the subset of [tex]V[/tex] of all points on the line
[tex]4x+3y=12[/tex]
We need to find if [tex]H[/tex] is a subspace of the vector space [tex]V[/tex].
In [tex]IR^{2}[/tex] all the possibilities for own subspace of the vector space [tex]IR^{2}[/tex] are :
We know that [tex]H[/tex] is the subset of [tex]IR^{2}[/tex] of all points on the line [tex]4x+3y=12[/tex]
If we look at the equation, the point [tex]\left[\begin{array}{c}0&0\end{array}\right][/tex] doesn't verify it because :
[tex]4x+3y=12\\4(0)+3(0)=12\\0=12[/tex]
Which is an absurd. Therefore, [tex]H[/tex] doesn't contain the origin (and [tex]H[/tex] is a line in [tex]IR^{2}[/tex]). Finally, it can't be a vector space of [tex]V=IR^{2}[/tex]