Question 109919: A. Solve the following quadratic equations. Make sure to show all your work. Do not use any method (e.g., factoring, completing the square, quadratic formula, graphing) more than twice. Use the graphing method at least once.
1. 3x2 + 11x – 20 = 0
2. x2 + 3x – 4 = 0
3. 3x2 – x – 1 = 0
B. State the different methods you used to solve each equation. Make sure that your work demonstrates both algebraic and graphing methods.: A. Solve the following quadratic equations. Make sure to show all your work. Do not use any method (e.g., factoring, completing the square, quadratic formula, graphing) more than twice. Use the graphing method at least once.
1. 3x2 + 11x – 20 = 0
2. x2 + 3x – 4 = 0
3. 3x2 – x – 1 = 0
B. State the different methods you used to solve each equation. Make sure that your work demonstrates both algebraic and graphing methods.
Answer by checkley71(5186) About Me (Show Source):
You can put this solution on YOUR website!
3X^2+11X-20=0
(3X-4)(X+5)=0
3X-4=0
3X=4
X=4/3 ANSWER.
X+5=0
X=-5 ANSWER.
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x^2+3x-4=0
x = (-b +- sqrt( b^2-4*a*c ))/(2*a)
x=(-3+-sqrt[3^2-4*1*-4])/2*1
x=(-3+-sqrt[9+16])/2
x=(-3+-sqrt25)/2
x=(-3+-5)/2
x=(-3+5)/2
x=2/2
x=1 answer.
x=(-3-5)/2
x=-8/2
x=-4 answer.
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3X^2-X-1=0
Y=3X^2-X-1 FOR THE GRAPHING METHOD:
graph( 300, 200, -6, 5, -10, 10, y = 3x^2 -x -1) (graph 300x200 pixels, x from -6 to 5, y from -10 to 10, y = 3x^2 -x -1).
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Teacher comments when I submitted this answer
1.The graphing method is incomplete.
2.The third equation is graphed, but the solutions are not identified. Where are they located? I need help with this
Answer by checkley71(8403)   (Show Source):
You can put this solution on YOUR website! THIS IS THE FACTORING METHOD
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3X^2+11X-20=0
(3X-4)(X+5)=0
3X-4=0
3X=4
X=4/3 ANSWER.
X+5=0
X=-5 ANSWER.
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THIS IS THE QUADRATIC EQUATION METHOD.
x^2+3x-4=0
x = (-b +- sqrt( b^2-4*a*c ))/(2*a)
x=(-3+-sqrt[3^2-4*1*-4])/2*1
x=(-3+-sqrt[9+16])/2
x=(-3+-sqrt25)/2
x=(-3+-5)/2
x=(-3+5)/2
x=2/2
x=1 answer.
x=(-3-5)/2
x=-8/2
x=-4 answer.
--------------------------------------------
3X^2-X-1=0
Y=3X^2-X-1 FOR THE GRAPHING METHOD:
 (graph 300x200 pixels, x from -6 to 5, y from -10 to 10, y = 3x^2 -x -1).
(.767,0)(-.43,0)(.1685,-1)
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Teacher comments when I submitted this answer
1.The graphing method is incomplete.
2.The third equation is graphed, but the solutions are not identified. Where are they located? I need help with this
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