4) The equation of a line in the slope intercept form is expressed as
y = mx + b
where
m represents slope
b represents y intercept. This is also the point where the line cuts across the y axis.
The formula for determining slope is expressed as
m = (y2 - y1)/(x2 - x1)
y2 and y1 are final and initial values of y corresponding to given points on the line and on the vertical axis.
x2 and x1 are final and initial values of y corresponding to given points on the line and on the horizontal axis. From the graph,
when x1 = - 1, y1 = - 4
when x2 = 1, y2 = 2
m = (2 - - 4)/(1 - - 1) = 6/2
m = 3
Slope of the line = 3
y intercept, b = - 1
Thus, equation of the line is
y = 3x - 1
