2Review of Slope-Intercept Form The slope-intercept form of a linear equation isy = mx + b.m represents the slopeb represents the y-intercept
3Review of Slope-Intercept Form Name the slope and y-intercept of each equation:m = -4, b =3m = , b = 5Rewrite as y = -8x , m = -8, b =Rewrite as y = 2x - 5, m = 2, b = -5Rewrite as y = x + 0, m = , b = 0Rewrite as y = 0x + 5, m = 0, b = 5y = -4x + 3y = 5 – x8x + y =4x - 2y =10y = xy = 5
4Write the equation of a line given... 1. Slope and y-intercept2. Graph3. Slope and one point4. Two points5. x - and y-intercepts
5Find the Equation of the Line Given the Slope and y-intercept Substitute m and b into y = mx + bm = -3, b = 1m = -2, b = -4m = 0, b = 10m = 1, b = 0m = 0, b = 0y = -3x + 1y = -2x - 4y = 0x + 10, y = 10y = 1x + 0, y = xy = 0x + 0, y = 0
6Find the Equation of a Line Given the Graph Find the y-intercept from the graph.Count the slope from the graph.To write the equation of the line, substitute the slope and y-intercept in the slope-intercept form of the equation.
10Find the Equation of a Line Given the Point and the Slope Use the Point-Slope Formula:is the given pointSubstitute m and into the formula
11ExampleWrite the equation of the line with slope = -2 and passing through the point (3, -5).Substitute m and into the Point-Slope Formula.
12Find the Equation of the Line Given Two Points Calculate the slope of the two points.Use one of the points and the slope to substitute into the Point-Slope formula.
13ExampleWrite the equation of the line that goes through the points (3, 2) and (5, 4).
14Find the Equation of the Line Given the x- and y - intercepts Write the intercepts as ordered pairs.The x-intercept 4 is the ordered pair (4, 0).The y-intercept -2 is the ordered pair (0, -2).Calculate the slope.Substitute the slope and the y-intercept (b) into the slope-intercept formula.
15Example Write the equation of the line with x-intercept 3 and y-intercept 2.x-intercept 3 = (3, 0); y-intercept 2 = (0, 2)Slope:y = mx + b