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Lesson 3 — Slope-Intercept Form (y = mx + b)

Understand m (slope) and b (y-intercept), graph lines, and model physical scenarios.

Identify m and b

In y = mx + b, m is the slope (rate of change, e.g., velocity in m/s), and b is the y-intercept (value of y at x = 0, e.g., initial position).

Example: y = 2x + 5 → slope 2 m/s (velocity), y-intercept 5 m (starting position).

Graph Quickly

Plot (0,b), then use m as rise/run (e.g., m = 3/2 → up 3, right 2).

Modeling: d = 0.5t + 10 describes a car moving at 0.5 m/s from a starting distance of 10 m.

Sandbox — Tune m and b

( , )
We compute m·x + b and compare to your y.
Adjust m and b. The line updates instantly.

Try it — Test your understanding

Question 1 of 5

For y = -2x + 3, the y-intercept is (0,3).

More practice (unlocks as you answer correctly)
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