An illustration shows a coordinate plane with 4 quadrants. The x-axis ranges from negative 9 to 9 in one unit increments, and the y-axis ranges from negative 11 to 11 in one unit increments. A line is graphed on the plane. An upward slanting line passes through points plotted at left parenthesis 1 comma 5 right parenthesis and left parenthesis 2 comma 10 right parenthesis.

The graph shows the proportional relationship. Derive the equation of the line y=mx
through the origin.

1 answer

To derive the equation of a line \(y = mx\) that passes through the origin and is proportional to the given points \((1, 5)\) and \((2, 10)\), we first need to find the slope \(m\).

Step 1: Calculate the slope between the points.

The formula for the slope \(m\) between two points \((x_1, y_1)\) and \((x_2, y_2)\) is given by:

\[ m = \frac{y_2 - y_1}{x_2 - x_1} \]

Using the points \((1, 5)\) and \((2, 10)\):

  • Let \((x_1, y_1) = (1, 5)\)
  • Let \((x_2, y_2) = (2, 10)\)

Substituting these values into the slope formula:

\[ m = \frac{10 - 5}{2 - 1} = \frac{5}{1} = 5 \]

Step 2: Write the equation of the line through the origin.

Since the line is proportional and passes through the origin, the equation can be expressed in the form:

\[ y = mx \]

Substituting in the slope we calculated:

\[ y = 5x \]

Conclusion

The equation of the line in the form \(y = mx\) that passes through the origin and describes the proportional relationship is:

\[ \boxed{y = 5x} \]