To derive the equation of the line in the form \( y = mx \), we need to determine the slope \( m \) of the line that passes through the origin and the given points \( (1, 5) \) and \( (2, 10) \).
First, we calculate the slope \( m \) using the two points. The formula for the slope between two points \((x_1, y_1)\) and \((x_2, y_2)\) is:
\[ m = \frac{y_2 - y_1}{x_2 - x_1} \]
Using the points \( (1, 5) \) and \( (2, 10) \):
- \( x_1 = 1, y_1 = 5 \)
- \( x_2 = 2, y_2 = 10 \)
Substituting into the slope formula:
\[ m = \frac{10 - 5}{2 - 1} = \frac{5}{1} = 5 \]
Now that we have the slope \( m = 5 \), we write the equation of the line that passes through the origin (0,0), which is:
\[ y = mx = 5x \]
Therefore, the equation of the line is:
\[ \boxed{5x} \]