SOLUTION: These quadratic equations are kicking my rear, please help. How do I find the Vertex and intecepts of: y = -x^2 + 6x -11 Thanks

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Question 24533: These quadratic equations are kicking my rear, please help. How do I find the Vertex and intecepts of:
y = -x^2 + 6x -11
Thanks
Answer by longjonsilver(2297) About Me  (Show Source):
You can put this solution on YOUR website!
OK, well, you do not say if you have done calculus. I assume you have.

dy/dx = -2x + 6
-2x + 6 = 0
-2x = -6
x = 3
--> y+=+-%283%29%5E2+%2B+6%283%29+-+11
--> y = -9 + 18 - 11
--> y = -2

so, the vertex is at (3,-2)

As to its intercepts...its solutions..its roots:

-x%5E2+%2B+6x+-+11+=+0
x%5E2+-+6x+%2B+11+=+0

Looking...it does factorise easily, so use the Quadratic formula. Put the number in to that and you will get a negative square root. Hence no real solution. If you have done Complex Numbers, the find the Complex roots of this equation.

jon