Chapter 2 Graphing and Writing Linear Equations

2.1 Graphing Linear Equations

Linear Equation An equation whose graph is a straight line. Anything with x to the first power

Solutions The points on the line Make the equation true

Determine if the ordered pair is a solution of the equation. y = 2x + 1 (3, 7 ) 7 = 2(3) + 1 YES The ordered pair (3,7) is a solution.

Making a Table to Graph 1. Solve for y: y=mx+b 2. A. Pick your x values (-1, 0,1) B. If “m” is a fraction and “b” is not then pick the + and – version of the denominator and 0 as your x -values 3. Plug in the x values into the equation to find the corresponding y values 4. Plot the (x, y) ordered pairs on the coordinate plane and draw a line

x y Find 3 solutions y = 2x + 1 X ValuesY=2x + 1 Y Values(x,y) 1 0 2(1) +1 3(1,3) 2(0) +1 1 (0,1) 2(-1) +1 (-1,-1)

x y Graph: xY=2/3x +5y(x,y) (2/3)(3) +5 7 (3,7) (2/3) (0) +5 5 (0,5) (2/3)(-3)+5 3 (-3,3)

Solve for ‘y’ Solve for ‘y’ means “get y all by itself”

x y Graph: -2x + y = 5 y = 2x + 5 XY=2x +5Y(x,y) 1 0 2(1) +57(1,7) 2(0) +55(0,5) 2(-1)+53(-1,3)

Types of Linear Lines Diagonal: when there are two variables Vertical: when there is only x Horizontal: when there is only y

Horizontal and Vertical Lines The graph of y= # is HORIZONTAL The graph x =# is VERTICAL

Graph y = 4 using 3-points xy 0 3 6

Graph x = 6 using 3-points xy

Homework TB: Page 46 (2-18 even, all, even