Example

Finding the Equation of a Line with Slope 25\frac{2}{5} and yy-Intercept (0,4)(0, 4)

To write the equation of a line when the slope and yy-intercept are known, perform a direct substitution into the slope-intercept form, y=mx+by=mx+b.

Given: slope m=25m = \frac{2}{5} and yy-intercept (0,4)(0, 4).

Step 1 — Identify the slope and yy-intercept. From the given information, m=25m = \frac{2}{5} and b=4b = 4.

Step 2 — Substitute into y=mx+by = mx + b.

y=25x+4y = \frac{2}{5}x + 4

The final equation of the line is y=25x+4y = \frac{2}{5}x + 4.

This simple substitution is the most efficient way to formulate a line's equation when both the rate of change and its starting value on the yy-axis are explicit.

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Updated 2026-05-03

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