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y − y
slope, m = 2 1
x 2 − x 1
y-intercept, b = y 1 − mx 1

Round m and b to the nearest
hundredths.

Figure 6-29: The Compute procedure

The ShowEquation procedure is shown in Figure 6-30. It uses two
variables (term1 and term2) and two subprocedures to properly format
the equation for display.

Figure 6-30: The ShowEquation procedure

The ShowEquation procedure considers the following special cases
while formatting the line equation:

• If the slope is 1, term1 will be set to x (instead of 1x).
• If the slope is –1, term1 will be set to –x (instead of –1x).
• term2 is formed using the proper sign (plus or minus) of the y-intercept.
• If the y-intercept is 0, the equation will have the form y = mx.

150 Chapter 6
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