Lesson 49 Writing equations in slopeintercept form Slopeintercept

Lesson 49 Writing equations in slope-intercept form

Slope-intercept form of an equation • The slope-intercept form is y=mx+b • where the value of m is the slope of the line and the value of b is the y-intercept.

Determining the slope and y-intercept • • y = 3 x -4 y= 5 x + 7 2 x + 3 y - 9 = 0 6 x - 3 y + 3 = 0

Solution of an equation in 2 variables • The solution of an equation in 2 variables is an ordered pair or set of ordered pairs that satisfies the equation. These solutions can be represented in a table of values or as a graph on a coordinate plane

Graphing an equation of a line in slope-intercept form • Graph using slope and y-intercept: • • y= 2/3 x y = 6 x 3 y + 5 x + 9 = 0 2 x + y + 5 = 0

Writing the equation of a line from a graph • Look for the y-intercept • Pick 2 good points to find the slope • Put them in the equation

practice • Write equations of lines in slope-intercept form

Lab 3 • Graphing linear functions

Graph y = 2 x + 7 • 1) enter the equation into the Y= • 2) press Y= key, then 2 X + 7 • 3) Press ZOOM and choose 6: standard to view the graph in the standard window. • 4) press TRACE to place the cursor on the y-intercept. (the coordinates are located on the bottom of the screen) • 5) you can center the screen on the y-intercept by pressing ENTER. • 6)you can use the TRACE function to view ordered pairs • 7) press ZOOM, select 5: square to get a better picture of the graph • 8) sometimes you can get better values (decimals to 1 decimal place) by using ZOOM then selecting Decimal

y= 3 x+6 • A) graph the equation in the standard viewing window • B) find the y-intercept • C) Use TRACE to find the coordinates of 3 other points( round to nearest hundredth) • Do the same for: y = -5 x+2