Example

Graphing y=3xy = -3x by Plotting Points

To graph y=3xy = -3x using the Point-Plotting Method, follow the three standard steps:

Step 1 — Find three solution points. Since yy is already isolated, choose convenient values for xx and compute yy:

  • x=0x = 0: y=3(0)=0y = -3(0) = 0, giving (0,0)(0, 0)
  • x=1x = 1: y=3(1)=3y = -3(1) = -3, giving (1,3)(1, -3)
  • x=2x = -2: y=3(2)=6y = -3(-2) = 6, giving (2,6)(-2, 6)

Step 2 — Plot the points. Mark (0,0)(0, 0), (1,3)(1, -3), and (2,6)(-2, 6) on a rectangular coordinate system. All three points fall on the same straight line, confirming the calculations are correct.

Step 3 — Draw the line. Connect the three points with a straight line, extend it across the grid, and add arrows on both ends. The resulting line is the graph of y=3xy = -3x.

Notice that this equation has no constant term — only the variable term 3x-3x. As a result, when x=0x = 0 the equation gives y=0y = 0, so the line passes through the origin (0,0)(0, 0).

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Updated 2026-04-21

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