SOLUTION: 20. Identify the axis of symmetry, create a suitable table of values, then sketch the graph (including the axis of symmetry). y=x^2-4x Okay, I took a stab at this but I don't

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Question 62210: 20. Identify the axis of symmetry, create a suitable table of values, then sketch the graph (including the axis of symmetry).
y=x^2-4x
Okay, I took a stab at this but I don't think I did it right. This is what I did.
x=-b/2a
y=ax^2+bx+c
- -4/2.1=
x=4/2
x=1
I have no idea how to create a suitable table of values in which my teacher told us to use excel to do the graph. I don't know how to plot a graph or even use excel.
I am screaming help to the fourth power, please.
Answer by venugopalramana(3286) (Show Source):
You can put this solution on YOUR website!
20. Identify the axis of symmetry, create a suitable table of values, then sketch the graph (including the axis of symmetry).
y=x^2-4x
COMPLETE THE SQUARE USING ALL X TERMS USING (A-B)^2=A^2-2AB+B^2..BY FINDING B AND THEN BY ADDING AND SUBTRACTING B^2
HERE A=X...-4X=-2XB...B=2.....SO ADD AND SUBTRACT 2^2 TO COMPLETE THE SQUARE
Y=[(X)^2-2(X)*2+2^2]-2^2=(X-2)^2-4
HENCE AXIS OF SYMMETRY IS X-2=0...OR...X=2
GIVE DIFFERENT VALUES FOR X AND FIND Y ..FOR EX..IF X =0...Y=0^2-4*0=0
X......0........2.......4........6..........-2.........-4....ETC...
Y=.....0.......-4.......0........12...........12.........32.....ETC
GRAPH WILL LOOK LIKE THIS