Graphs of Straight Lines
5.2 Graphs of Straight Lines
•Linear equations in two variables ( y = mx + b, Ax + By = C)o The graph of a linear equation is a straight line
o A solution of a linear equation is an ordered pair (x, y) that makes the equation true
statement
Ex. a) Is (0, -1) a solution of y = 2x –1?
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b) Is (2, -2) a solution of y = 3x + 8?
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Ex. Find the ordered pair solution of y = -3x that corresponds to x = -1
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Ex. Find the ordered-pair solution of that corresponds to x = -4
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To graph a linear equation, find two (or more) ordered-pair solutions by choosing any value for x and finding the corresponding value of y.•x and y-intercepts ( x, 0), (0, y). To find the x-intercept you let y = 0, and to find the yintercept you let x = 0
• Solve Ax + By = C for y• Graphs and equations of vertical and horizontal lines
Ex. Graph:
a) y = x – 2  |
b) y = -3x + 1 |
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d) –2x + y = 1
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| e) x – 4y = 8
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f) y = -3 ( Horizontal line)
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| g) x = 1 ( Vertical line)
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h) x + 2y = 6
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Ex. Solve 2x +3y = 9 for y: ___________________________________________
HW page 270 # 3 – 23 every other odd, 29-57 every other odd, 63–113 every other odd