Find the equation of the plane passes through the points $(3, 0, 0), (0, 4, 0) and (0, 0, 5).$

Plane passes through the points $(3, 0, 0), (0, 4, 0) \mathrm{and} (0, 0, 5).$ is

$\frac{x}{a}+\frac{y}{b}+\frac{z}{c}=1$

$\Rightarrow \frac{x}{3}+\frac{y}{4}+\frac{z}{5}=1$

This is the required equation of plane.