SlopeIntercept Form
 Launch GrafEq
by double clicking its icon. Click on the title screen to remove it.
 Type in the equation
y=Mx+B.
 Press the Tab key, and assign a value to M by typing
“M=1”.
 Press the Tab key again, and assign a value to B by typing
“B=0”.
The input window is now complete.
 Press the Return key to get the
Create View window.
The default mode (Cartesian) is correct,
and the default bounds (10 to 10) are fine for both
xaxis and yaxis.
 Click on the Create button.
GrafEq will plot the graph
of y=1*x+0.
 The sidebar is currently showing general information.
To display ticked axes:
 click on the General button and drag the highlight bar to
Ticks;
 under the Simple submenu, click on the box with dense
ticks and crosses;
 click the Active checkbox to display the ticks and crosses.
 Now, copy the graph onto the coordinate system graph paper.
Label it “y=1*x+0”.
Make a dot where the line crosses the yaxis
and label it “0”.
This point is called the yintercept and its yvalue is 0.
 Next, change the value of B from 0 to 3:
 click on the Ticks button and drag the highlight bar to
General;
 click on the Relation #1 button to display the relation entered;
 click on the B=0 constraint, and change 0 to 3.
 Repeat the necessary steps, as described above, to plot
y=1*x+(3).
Label the new line on your graph paper as “y=x3”.
Q: What is the yintercept of this line?
Label the point where the line crosses the yaxis as “3”.
 Repeat the necessary steps for
B=5.
Q: What is the yintercept of this line?
Q: How should you label the yintercept accordingly?
 Q: Where will the line with equation
y=x+7 cross the yaxis?
Confirm your answer with GrafEq,
by graphing y=x+7
(by setting B=7).
 Q: Where do you think the graph of y=2x+5
will cross the yaxis?
Confirm your answer with GrafEq, setting
M=2 and B=5.
 Now, in relation #1, set
M=4 and
B=5.
 Under the Graph menu,
choose New Relation to get the
Graph #1 Relation #2 input window.
 Enter the equation
y=0.2x+5.
Press the Return key to see both
Relation #2 and Relation #1 on Graph #1.
 Repeat the necessary steps for the equation
y=3x+5.
 Q: What do the three lines have in common? Why?
Conclusion:
The graph of y=Mx+B is a line with yintercept = _____________.

