Interactively study straight lines

• Drag either of the blue points on the line.
• The resulting change in the line depends on the constraint setting:

None

The points may be dragged anywhere, redefining the line,

X

The x coordinate of each point is fixed, so movement is only up or down,

Y

The y coordinate of each point is fixed, so movement is only left or right,

X + Y

The point moves only along the current line.

• Clicking and dragging the line itself allows translation of the line.
• If Intercepts is selected, the X and Y intercepts are shown in green.
• Values are shown as fractions or decimals according to the state of the Decimals setting.
• The equation of the current line is constantly displayed and updated as points are moved. Alternatively it can be entered using the Enter equation… dialog in either standard form, i.e. x - 2y + 4 = 0 or in gradient-intercept form, i.e. y = 1/2x + 2.
• Click and hold the chart background to bring up a magnifier.