SOLUTION: we are graphing quadratic equations and the teacher isn't explaining it in simpler terms it is a function and i need help with the steps to solve the fuction is y=-2x^2-2x+3 and we

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Question 379489: we are graphing quadratic equations and the teacher isn't explaining it in simpler terms it is a function and i need help with the steps to solve the fuction is y=-2x^2-2x+3 and we have to graph it. can you help me and give me the steps?
Answer by mananth(16946) (Show Source):
You can put this solution on YOUR website!
y=-2x^2-2x+3
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first find the x intercepts.
plug y =0
-2x^2-2x+3=0
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Find the root of the equation using quadratic formula.
discriminant b^2-4ac= 28
x1=(2+sqrt(28))/-4
x1=-1.82
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x2=(2-sqrt(28))/-4
x2=0.82
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The x intercepts are (0,-1.8) & (0,0.82)
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Using the equation y = -2x^2-2x+3
find the vertex of the parabola
a=-2, b=-2
h=(-b/2a)
h=(2/-4)
h=-1/2
plug the value of (-1/2) in the equation to get the y value of the vertex
y= -2*(1/4)-2*-1/2+3
y=-0.5+1+3
y=3.5
Vertex ( -1/2 , 3.5)
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since x^2 is negative the parabola opens downwards
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generate various value of y for different values of x
x=-1, y=3
x=1,y=-1
x=-2,y=3
x=2,y=-9
x=2,y=-9
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use a calculator or plot points and join the curve.