a lgebra 5.7 5.7 point-slope form. l earning t argets language goal students will be able to explain...
TRANSCRIPT
LEARNING TARGETS
Language Goal Students will be able to explain how to
graph a line and write a linear equation using point-slope form.
Math Goal Students will be able to write a linear
equation given two points.Essential Question Why is it important to have different
forms to graph a line?
EXAMPLE 1: USING SLOPE AND A POINT TO GRAPH
Steps are the same as if you were given a y-intercept
Step 1: Plot the given point
Step 2: Use the slope to move from the given point to the next point.
Step 3: Connect the points.
EXAMPLE 2: WRITING LINEAR EQUATIONS IN POINT-SLOPE FORM
Write an equation in point-slope form for the line with the given slope that contains the given point.
A. Slope = (-3, 0) B. Slope = -7; (4, 2)
EXAMPLE 2: WRITING LINEAR EQUATIONS IN POINT-SLOPE FORM
Write an equation in point-slope form for the line with the given slope that contains the given point.
C. Slope = 0 (-2, -3) D. Slope = 2; (, 1)
EXAMPLE 3: WRITING LINEAR EQUATIONS IN SLOPE-INTERCEPT
FORM
Slope Intercept Form: y = mx + b
Yesterday: Step 1: Find the y – intercept by...
Plugging in the slope and the ordered pair. Solve for b.
Step 2: Write the equation using the slope and b.
Today:Step 1: Write the equation in point-slope form.Step 2: Write the equation in slope-intercept form by solving for y.
EXAMPLE 3: WRITING LINEAR EQUATIONS IN SLOPE-INTERCEPT
FORM
Write an equation in slope-intercept form for the line with the given slope and contains the point.
A. Slope = -4 (-1, -2) Yesterday’s method Today’s method y = mx + b
EXAMPLE 3: WRITING LINEAR EQUATIONS INS SLOPE-INTERCEPT
FORM
Write an equation in slope-intercept form for the line with the given slope and contains the point.
B. Slope = C. Slope = 3; (-1, 4)
EXAMPLE 4: USING TWO POINTS TO WRITE AN EQUATION.
Step 1: Find the slope. Step 2: Substitute the slope and one of the
points into the point-slope form Step 3: Write the equations in slope-
intercept form by solving for y.
EXAMPLE 4: USING TWO POINTS TO WRITE AN EQUATION.
Write an equation in slope-intercept form for the line through the two points.
A. (1, -4) and (3, 2) B. (4, -7) and (0, 5)
EXAMPLE 4: USING TWO POINTS TO WRITE AN EQUATION.
Write an equation in slope-intercept form for the line through the two points.
C. (1, -2) and (3, 10) D. (6, 3) and (0, -1)
EXAMPLE 5: WORD PROBLEMS
The cost to place an ad in a newspaper for one week is a linear function of the number of lines in the ad. The costs for 3, 5, and 10 lines are shown. Write an equation in slope-intercept form that represents the function. Then find the cost of an ad that is 18 lines long.
Lines 3 5 10
Cost $ 13.50
18.50
31
EXAMPLE 5: WORD PROBLEMS
At a different newspaper, the costs to place an ad for one week are shown. Write an equation in slope-intercept form that represents this linear function. Then find the cost of an ad that is 21 lines long.Lines 3 5 10
Cost $ 12.75
17.25
28.50
SUMMING IT UP!
Use the two points in the
formula to find the slope. Then use the slope and one of the points to write the equation in
point-slope form.
If the slope is m and y –intercept
is b, then the equation is y = mx + b
Use the slope and the point to
write the equation in
point-slope form.