Solve the equation $5y + 10 = 3y + 4$ and represent the solution on $(1)$ the number line and $(2)$ the Cartesian plane.

(Y = -3) Step $1$: Solve the equation for $y$.
$5y + 10 = 3y + 4$
$5y - 3y = 4 - 10$
$2y = -6$
$y = -3$
Step $2$: Representation on the number line.
On a horizontal number line,mark the point at $-3$.
Step $3$: Representation on the Cartesian plane.
The equation $y = -3$ represents a horizontal line parallel to the $x$-axis,passing through the point $(0, -3)$.