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Published byJasper Harrington Modified over 9 years ago
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Warm ups Graph completely (with all parts from worksheet)
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11-2 Solving Quadratic Equations by Graphing Objective: To find the roots of a quadratic equation. Standard 21.0
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Homework Questions? View Answer Key
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Example 1 Let’s use the warm up problem! Look at where the parabola crosses the x axis… These points are the ROOTS! The roots are the x-intercepts. Look at your warmup graph… where does it cross the x axis?
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Look at the roots.. How else did we learn how to solve these? Factoring!
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What are the roots?
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Roots can look like… 2 roots1 rootNo real roots
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ROOTS FOR TOO #2 are like this Does not fall on a nice, whole number Between 2 numbers: write as inequality Start all the way to the left Write with “<“ signs “x” in the middle of the 2 #’s 2 < x < 3 6 < x < 7
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TOO – BAD slide. Solve by graphing. Roots 1. 2. 3. 4. Estimate if not exact. If not sure if it is exact, then try to factor! Vertex in on x-axis Does not cross x-axis
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Example 2 Graph given roots {-2,0} and minimum (-1,-1) Vertex!!
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RECAP OF ROOTS 2 Roots Crosses x-axis twice Vertex is below and opens up Vertex is above and opens down Whole Numbers Answer: (x,0) and (x,0) Between 2 Numbers Answer: # < x < # # < x < # 1 Root Vertex is on the x-axis Answer is vertex! (x,0) No Roots Does not cross x-axis Vertex is above and opens up Vertex is below and opens down Answer: None
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SIDE NOTE Y-intercept, x always equals 0 so... EX#1 y = 1/2x 2 – 2x + 2 y = 1/2(0) 2 – 2(0) + 2 y = 0 – 0 + 2 y = 2 (0,2) y-intercept Y-intercept is ALWAYS “c” Ex: y = 2x 2 – 5x + 26 (0,26) EX #2 y = -x 2 – 2x + 3 y = -(0) 2 – 2(0) + 3 y = 0 – 0 + 3 y = 3 (0,3) y-intercept
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Homework Pg. 625 # 17-19, 20-23, 35-38 Graph the parabola first, THEN see where it crosses the x-axis. The point(s) at which it crosses (once, twice, or none) are the roots. Write the roots in brackets { } Use graph paper!
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Math Lab Warmup: Simplify
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Simplify
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Review Commonly missed test questions: factor.
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Review Commonly missed test questions: factor.
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Review Commonly missed test questions: solve
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Review Commonly missed test questions: solve
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Homework Groups Let’s get into the same homework groups that we worked on yesterday. Once you are seated, raise your hand if you are all finished, or finish, your homework.
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If you finish homework.. Either graph or solve using quad. Formula: Depending on what you’ve learned so far
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