Straight Line Graphs


linear functions have graphs which are straight lines.

the general equation of a linear function is ax + by + c = 0.

the exponents of both the x term and the y term are 1.

another often used form of linear functions is y = mx + c.

Key Skills

  • recognise that a function has a straight line graph
  • sketch the graph of a linear function by plotting points
  • find the x and y-intercepts of linear functions
  • use the gradient / intercept form of a linear functions i.e. y = mx + c


linear functioncartesian graphcoordinatesordered pairorigin,gradientverticalhorizontalspreadsheet, x-intercept, y-intercept, x-axis, y-axis.