Linear Graphs

Reading and plotting a point

• The grid used throughout this course has a horizontal x-axis and a vertical y-axis, meeting at the origin
• The origin is the point (0, 0), and every other point is described by how far it lies from there in each direction
• A pair of coordinates is written in brackets with the horizontal value first: (x, y)
• Positive x moves right and negative x moves left; positive y moves up and negative y moves down
  • (4, 3) sits four to the right and three up
  • (−2, −5) sits two to the left and five down
• Plot a point with a small cross or a solid dot, and write its letter beside it when the question names it, so it is clear which point is which

• Check the scale on the axes before counting: one square is frequently worth more than one unit, and assuming otherwise puts every answer out by a factor