Linear Graphs Revision

Represented by "m" in the linear equation

+ slope rises from left to right

 −  slope falls from left to right

zero slope create a straight horizontal line

undefined slope creates a straight vertical line

Divide rise by run to find slope

 $m\ =\frac{y_2\ -\ y_1}{x_2\ -\ x_1}$  

Represented by "b" in an equation

Shows where to line meets/cuts the y-axis (x=0)

When a line crosses the Y- axis, the point where it cuts through is called the intercept.

1) Use two points on graph to find slope (m)

2) Identify the y-intercept (b)

3) Substitute these two values into the standard equation y= mx + b

1) Use the coordinates of two points to determine the slope (m)

2) Substitute this value for the slope (m) into the equation y = mx + b

3) Substitute the coordinates of one of the two points on the line into this new equation and solve for the unknown (b)

4) Substitute the values of m and b into the general equation y=mx + b to obtain the equation of the straight line