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Solving Systems By Elimination.notebook
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Solving Systems Algebraically
Eliminaon
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Step 1
• Add/subtract the equaons to eliminate one of the variables.
• If you can’t eliminate a variable with the equaons as they are, mulply enre equaons by a coefficient to make coefficients that will cancel.
Solving By Eliminaon
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Step 2
• Once you have added/subtracted the equaons and have eliminated one of the variables, solve for the remaining variable.
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Step 3• Find the other variable by pung the soluon already found
into one of the original equaons.
Write your soluon as a coordinate pair.
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Review Example 1
• 3x + 2y = 19
• 5x – 2y = 5
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Graph Confirmaon
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Example 2• With quadracs, the method is the same but we solve for the
variable by factoring the equaon.
• y = 3x2 + 6x – 10
• y = 12x – 1
Because one is a quadrac and one is linear, eliminate the y’s by subtracon to create another quadrac that we will solve using
our factoring skills.
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Soluon:
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Graphical Confirmaon
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Quadrac – Quadrac Example
• 6x2 – x – y = –1
• 4x2 – 4x – y = –6
• (2x + 5)(x – 1) = 0
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Word Problems Example 1
1. Skeet shoong requires a shooter to hit a projecle while in flight. The target is launched on a path defined by h(t) = –2t2 + 20t, where h(t) is the height of the projecle in meters and t is the me of the projecle in seconds, and the gun is shot along the line h(t) = 14t. Aer how many seconds does the shooter hit the target? How high is the projecle when it is hit?
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Example 2:• Terri make a good hit and the baseball travels on a path modeled by
• Ruth is in the ouield directly in line with the path of the ball. She runs toward the ball and jumps to try and catch it. Her jump is modeled by the equaon . In both equaons, x, is the horizontal distance in metres from home plate and h is the height of the ball above the ground in metres.
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Example 3• Determine two integers that have the following relaonships: Fourteen
more than twice the first integer gives the second integer. The second integer increased by one is the square of the first integer.
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Example 4• A diver is using training videos to improve her skill from a 3‐m
springboard. Her coach uses video analysis to plot her height above the water. Could you represent this situaon as a graph?
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Soluon:• What does the point of
intersecon mean?
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Assignment• p. 451 #4, 7, 10, 13, 15, 16b, 23