# quadratic graphs and completing the square

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#1
when I am asked " which of the following could be an equation of the graph?" what do I need to consider? I though maybe the C value is A squared+BX+C but what if there are two completed square solutions that give the same Y intercept. For example,
y= (x+3 )squared-1
y= (x-3 )squared+1 these both give the same C value so I'm very confused.
Last edited by lavely; 4 days ago
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4 days ago
#2
These give different c values, the first one would give c=8 and the second one would give c=10
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#3
(Original post by beckyyw)
These give different c values, the first one would give c=8 and the second one would give c=10
sorry there was a typo my fault one of the signs in the bracket was a negative -
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4 days ago
#4
Even thought the signs in the brackets are different you would still get different c values.
Here: (x-3)squared + 1 = xsquared - 6x + 9 + 1, c=10
And: (x+3)squared - 1 = xsquared + 6x + 9 - 1, c=8
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