2-dimensional representation of a multiple regression function

Supposing I have a multiple regression population function of the form:

${Y}_{i}={\beta}_{1}+{\beta}_{2}{X}_{2i}+{\beta}_{3}{X}_{3i}+{u}_{i}$

with ${X}_{3i}$ a dummy variable (only takes values $0$ and $1$).

I am given a sample of points. Although the latter takes place in 3 dimensional space, the question states "its results can be represented in $Y$ vs ${X}_{2}$ space". I don't understand how graphing $Y$ vs ${X}_{2}$ will give us a 2 dimensional representation of our population regression function. Isn't ${X}_{3i}$ being completely omitted?

Supposing I have a multiple regression population function of the form:

${Y}_{i}={\beta}_{1}+{\beta}_{2}{X}_{2i}+{\beta}_{3}{X}_{3i}+{u}_{i}$

with ${X}_{3i}$ a dummy variable (only takes values $0$ and $1$).

I am given a sample of points. Although the latter takes place in 3 dimensional space, the question states "its results can be represented in $Y$ vs ${X}_{2}$ space". I don't understand how graphing $Y$ vs ${X}_{2}$ will give us a 2 dimensional representation of our population regression function. Isn't ${X}_{3i}$ being completely omitted?