1. HOW TO WRITE THE EQUATION OF A LINE Y = MX + B A SIX STEP APPROACH

2. STEP ONE 1.EX: Y – Y = M (1,2) (2,3) X – X 3 – 2 = 1 2 – 1 2.FIND THE SLOPE BY GRAPHING THE POINTS EX: how much does it go up divided by how much does it go over.

3. STEP TWO SUBSTITUTE “M” Y = MX + B THE NUMBER YOU GOT FROM STEP ONE GOES INTO THE EQUATION FOR “M.” Y = 1X + B

4. STEP THREE PICK A POINT CHOOSE EITHER OF THE COORDINATES. THEY ARE BOTH ON THE LINE SO IT DOES NOT MATTER. (1,2) (2,3) (1,2) HINT: IT IS TYPICALY EASIER TO CHOOSE THE SMALLER OF THE COORDINATES.

5. STEP FOUR SUBSTITUTE “X & Y” TAKE THE NUMBERS YOU CHOSE FROM STEP THREE AND PUT INTO THE EQUATION FOR “X & Y.” 2 = 1(1) + B

6. STEP FIVE SOLVE FOR “B” USING THE EQUATION YOU SET UP IN STEP FOUR NOW GET “B” ISOLATED. AKA ALL ALONE. BY USING INVERSE OPERATIONS 2 = 1(1) + B 2 = 1 + B MULITPLIED BY ONE TO SIMPLIFY -1 = -1 SUBTRACT BY ONE ON EACH SIDE TO SIMPLIFY 1 = B

7. STEP SIX SUBSTITUTE “B” USING THE VALUE YOU JUST SOLVED FOR IN STEP FIVE, TAKE THAT NUMBER AND SUBSTITUTE IN FOR “B.” Y = 1X + 1 YOU NOW HAVE THE EQUATION OF A LINE THAT GOES THROUGH TWO POINTS.

8. EXTENSION Y = MX + B FROM A SCATTER PLOT or TABLE OF VALUES Write the equation of the line that you think fits best for the data. Using the information in the table write the equation of the line. Hint: graphing might help with the image JULY147,000 AUGUST146,450 SEPTEMBER146,000 OCTOBER145,500 NOVEMBER145,100 DECEMBER144,800 MONTH$ OWED JANUARY150,800 FEBRUARY150,000 MARCH149,850 APRIL149,200 MAY148,500 JUNE147,800

9. Good and Bad graph Table of Values for height vs wingspan 162163 179181 163165 163 164165 172 178179 162161 163161 158156 157158 160161 159 158160 162164 The graph on top is a representation of positive correlation and has meaning since it show a relationship between the height and wingspan of the individuals. Where the graph on the bottom has no meaning since the X axis shows frequency of individuals with the measured wingspan. So no correlation is shown between the two sets of data.

10. COPYRIGHT© 2006 JEREMIAH BASKIN