Find the value of m by solving the following equations: 1. m = 7 – 5 / 8 – 3 2. m = (-3) – 6 / 5 – (- 1) 3. 4 – (-4) / 2 – 2 4. m = / 1 – 6

By the end of the day today, IWBAT… Calculate the slope of a line given two points. By the end of the day today, IWBAT… Calculate the slope of a line given two points. Why it matters in LIFE : Slope (or steepness) is seen all around us, from the hills we drive on, ramps we skate down, and stairs we climb. Slope is also a key concept on the Algebra STAAR. Why it matters in THIS CLASS : Over the next few weeks we will become slope masters – calculating slope from points, graphs, and other lines.

 Identify the following on the coordinate plane below › x-axis and y-axis › The origin

 Plot the following points

 Name the coordinates of the following points

 A number that describes the steepness of a line.  Can be determined from any two points.  Rise over Run

 We can use this formula to determine slope from two points  It means the same thing as rise over run  Change in y over change in x

 Calculate the slope of a line that goes through points (3, 5) and (8, 7) The slope is 2/5 The slope is positive

 Look back at the Do Now problems, we were actually calculating slope!  Slope can be positive, negative, zero, or undefined.

 Use the slope formula to determine the slope of line AC a. -5/6 b. 5/6 c. 6/5 d. -6/5

 Use the slope formula to determine the slope of line AD a. -6 b. 0 c. Undefined d. 6

 Use the slope formula to determine the slope of line CD a. -1/6 b. 1/6 c. 6 d. -6

 Use the slope formula to determine the slope of line AB a. 5 b. 0 c. Undefined d. -5

 Complete Riddle Me This worksheet  Act out the Riddle as you finish.

Ex. Write the equation of the line through (0,4) and (-1, 2) 1. Calculate the slope : m= 2 – 4 / -1 – 0 = -2 / -1 so m = 2 Y = 2x + b 2. Solve for b by plugging in point (0, 4) for x and y y = 2x + b 4 = 2(0) + b 4 = b  Y = 2x + 4 y = mx + b Slope: m y-intercept: b

Write an equation for each line in slope- intercept form 1. The line through (-1, 0) and (1, 2) 2. The line through (6, 6) and (3, -3) 3. The line through (2, -2) and (-8, 3)

 What if we only know ONE point on the line?  Can we use slope-intercept?

y – y 1 = m(x – x 1 ) Slope: m Point: (x 1, y 1 ) Ex. Write the equation of the line with a slope of 3 through (2,1) in point-slope form this tells us that m = 3 Plug in 3 for m and the y and x from the coordinate pair for the points in the equation. y – 1 = 3(x – 2)

Ex. The line through points (2, 0) and (0, 3) in point-slope form 1. Calculate the slope : m= 3-0 / 0 – 2 = 3 / -2 = -3/2 2. Plug in one point : y – 0 = -3/2(x – 2) y = -3/2(x – 2)

Write an equation for each line in point-slope form. 1. The line with slope 6 through (3, -4) 2. The line with x-intercept 3 and y-intercept –5 3. The line with x-intercept 2 and y-intercept -1

 Complete the worksheet by yourself