SECTION 8.1
RECTANGULAR COORDINATE SYSTEM
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Plot (3,2) , (4,0) , (5,0) , (-5,0) (0,6) (-3,2) , (-4,0) , (0,1) , (1,0) (-7,-6)
Finding Solutions to a linear equation
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Is (3,4) a solutions to the equation x + y = 7 ?
Complete the ordered pairs so that they are solutions of the equation
x  y  10
x
x
y
y
x
y
SECTION 8.2
Graphing linear equation
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The coordinates that make the following equations true are called solutions to the equation.
x  y  10
x
y
y
x
x
y  3
x
y
x5
x
y
y
Graphing linear equation
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X- and Y- intercepts
X-intercept
4 x  5 y  20
Y-
intercept
Let y=0
x  2y  2
X-intercept
Let y=0
3x  2 y  15
X-intercept
Let y=0
y
1
x3
2
X-intercept
Let y=0
Let x=0
Y-intercept
Let x=0
Y-intercept
Let x=0
Y-intercept
Let x=0
Sketch the graph of each line by substituting three values for x.
1
1) 𝑦 = 3 𝑥 + 4
x
y
x
3
3) 𝑦 = 2 𝑥
x
6
2) 𝑦 = 5 𝑥 − 5
y
y
3
4) 𝑦 = − 2 𝑥 − 1
x
y
Sketch the graph of each line by using the pattern.
3
5) 𝑦 = − 4 𝑥 + 1
x
y
1
6) 𝑦 = − 5 𝑥 − 4
x
y
7) 4𝑥 + 5 = 5𝑦
x
y
9) – 𝑦 − 4 + 3𝑥 = 0
x
8) 𝑥 − 𝑦 + 3 = 0
x
y
10) −3𝑦 = −5𝑥 + 9
y
x
y
Write the slope-intercept form of the equation of each line given the slope and the yintercept.
1) Slope = 2, y-intercept = 5
4) Slope = −1, y-intercept = −2
2) Slope = −6, y-intercept = 4
3
5) Slope = − 4,
3) Slope = 1, y-intercept = −4
y-intercept = −1