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Stack and Subtract/Rise over Run to find slope notes Absent copy Mon 4/15 Stack and subtract to find slope Here are 2 ordered pairs that can be graphed: (3,4) (5,2) you can find the slope of this line by stacking the ordered pairs and subtracting the x’s and y’s. Then put the new y on top of the new x. x 3 , 4 (3,4) - (5,2) Hint: what happens with the – sign outside of the grouping? (-2,2) y = 2 Slope is -1 x,y x -2 5 , 2 Example 1 • Find the slope of the line that goes through the following points. (-4,8) and (5,-1) (-4,8) - (5,-1) distribute the neg. (-4,8) +(-5,1) -9, 9 x,y Slope is 9 or -1 -9 • Does it matter what ordered pair we stack first when using the stack and subtract method to find slope? YES or NO • What do we have to do with the neg. sign outside of the groupings? • You have to distribute the neg. sign through the parenthesis then rewrite. • How do we write the slope y or x x y Example 2 • Find the slope of the line that goes through the following points. (-3,3) and (2,1) ( 2, 1) -(-3,3) distribute the neg. ( 2, 1) +( 3,-3) (5, -2) x, y Slope: -2 5 • Does it matter what ordered pair we stack first when using the stack and subtract method to find slope? YES or NO • What do we have to do with the neg. sign outside the groupings? • You have to distribute the neg. sign through the parenthesis then rewrite. • How do we write the slope y or x x y Rise over Run method to find slope count the change in y = Rise count the change in x Run 4 = -2 2 slope is -2 Example 3 • Identify the slope of the line. • What do we all ready know from the direction of the line? • That the slope is neg. • What is the change in y? 3,5 • 2 ,0 • What is the change in x? • 5 = 1 5 Slope is____-1_____ The change in y is 5. The change in x is 5. • How do we write the solution to the slope? y or x x y Example 4 • Identify the slope of the line. 1, 5 • What do we all ready know from the direction of the line? • The slope will be positive. • The change in y is 8. • The change in x is 2. • What is the change in y? • What is the change in x? 3, 3 slope 8 =4 2 • How do we write the solution to the slope? y or x x y