How to get the equation of graph 1 over V vs R

The graph shows Voltage (V) on the y-axis and Resistance (R) on the x-axis. It appears to be a straight line passing through the origin.

This is given by $y = mx$, where $m$ is the slope.

So the equation becomes $V = mR$.

The slope is calculated as the change in $y$ divided by the change in $x$. From the graph, we can pick two points. Let's use the origin $(0,0)$ and another point, for example, $(2 \text{ } \Omega, 4 \text{ } V)$.
The slope $m = \frac{\Delta V}{\Delta R} = \frac{4 \text{ } V - 0 \text{ } V}{2 \text{ } \Omega - 0 \text{ } \Omega} = \frac{4 \text{ } V}{2 \text{ } \Omega} = 2 \text{ } \Omega^{-1}$.

$V = (2 \text{ } \Omega^{-1})R$.

The equation of the graph is $V = 2R$.

V = 2R