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Section 2.1Graphs Points & Ordered Pairs (x,y) Quadrants I II III IV Solutions to Equations x-intercepts Nonlinear Equations

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Points and Ordered Pairs

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Plotting Points aka Graphing Points

( , ) x-value, y-value

– ++–

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Find the Coordinates of these PointsA: (-5,1)

B: (-3,2)

C: (0,4)

D: (3,3)

E: (1,0)

F: (0,-3)

G: (-5,-4)

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Quadrants and Coordinate Signs

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Solutions to EquationsAny point on a graphed equation is a Solution

Why is (5,5) Why is (-3,3) Why is (-2,-1)a solution? a solution? a solution?

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How to Check if a Point is a Solution Is (2,-4) a solution of 4x – 3y = 22 ? Substitute 2 for x, and -4 for y 4x – 3y = 22

4(2) – 3(-4) 22 ? 8 + 12 22 ? 20 ≠ 22 No, not a solution

Is (-3,-5) a solution of y = 2x + 1 ? y = 2x + 1

-5 2(-3) + 1 ? -5 -6 + 1 ? -5 = -5 Yes, it’s a solution!

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Graph the equation y = x

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Graph the equation y = 2x

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Graph the equation y = -½x

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Graph the equation y = |x|

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Graph the equation y = x2 - 5

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Warm up that Ol’ Homework… Next time: Section 2.2 Functions