Graphing a Linear Equation
Graph y = 2x + 1 What we do is
pick any value for x that we want and substitute it into the
equation.
So let x = 1 and substitute.
So y = 2x + 1 becomes y = 2(1) + 1 and hence y = 3 when x = 1. Therefore
the first ordered pair is (1,3).
Next let us select -1 as the next value
for x and substitute it into the equation. Therefore y = 2x + 1 becomes y
= 2(-1) + 1 and hence y = -1 when x = -1. Thus the second ordered pair is (-1,-1)
So lets select
2 for x and substitute it into the equation. y = 2(2) + 1
Therefore y = 5 and the ordered pair is (2,5).
The chart below is used to organize and simplified the procedure we just
completed. The selected x value is on the left and the y value obtained after
substituting the x value into the equation is on the right.
So lets graph the linear equation y =
2x + 1 using the ordered pairs from the chart (1,3), (-1,-1),(2,5) answer
return to PCTC