Linear Graphs revision

Represented by "b" in the equation

+ slope rise from left to right

 $-$  slope fall from left to right

zero slope = straight horizontal line

un defined slope = straight vertical line

Divide rise by run to find slope

 $b=\frac{y_2-\ y_1}{x_2-x_1}$  

Represented by "a" in an equation

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

1) Identify the y-intercept (a)

2) Use two points on graph to find slope (b)

3) Substitute these two values into the standard equation y=a+bx

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

2) Substitute this value for the slope (b) into the equation.

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

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