Algebra 1 Basic

Slope-Intercept Grapher

Enter slope m and y-intercept b for y = mx + b to instantly graph the line and see every key feature — x-intercept, direction, slope triangle, and more.

Interactive canvas graph
Slope triangle drawn
Fraction form slopes
Live
Line Input — y = mx + b
y = mx + b
Decimal OK — 0.5 = ½
Where line crosses y-axis
Viewing Window (optional)
Default is −8 to 8. Change to zoom in or out.
Examples
Key Features
Enter m and b above, then press Graph It to see the line's key features and graph.
Equation
y = 2x + 1
Slope m
y-intercept b
Direction
    Key Features
    Graph: y = mx + b
    Understanding y = mx + b
    y = mx + b

    m is the slope — it measures the steepness and direction of the line. A positive m means the line rises left to right; a negative m means it falls. The larger the absolute value of m, the steeper the line.

    b is the y-intercept — the value of y when x = 0. It is the exact point where the line crosses the y-axis: (0, b).

    Together, m and b completely determine any non-vertical line. Two lines with the same m are parallel; two lines with slopes that multiply to −1 are perpendicular.

    Slope = rise ÷ run. A slope of 3/2 means go up 3, right 2 from any point on the line.
    How to Graph from Slope-Intercept Form

    Follow three steps to graph any line in y = mx + b form:

    • Step 1 — Plot the y-intercept: Put a point at (0, b) on the y-axis.
    • Step 2 — Use rise/run: From (0, b), move rise units vertically and run units horizontally to find a second point.
    • Step 3 — Draw the line: Connect the two points and extend in both directions.
    • Find the x-intercept: Set y = 0 and solve: x = −b / m.
    If m is negative, the rise is negative — move DOWN, then right.

    Lines still feel slippery?

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