SOLUTION: Find the axis of symmetry. y = x^2 + 5x - 7 Please show me how to do this. Thanks

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Question 42461: Find the axis of symmetry.
y = x^2 + 5x - 7
Please show me how to do this. Thanks
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
y = x^2 + 5x - 7
There are either no real roots, one real root, or 2 real roots
To find the axis of symmetry, look at the quadratic equation
where the equation above is represented by
+ax%5E2+%2B+bx+%2B+c+=+0
The roots are values for x where y = 0
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
notice this can be written as
x+=+-b%2F%282a%29+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%2F%282%2Aa%29+
separate the 2 solutions
x+=+-b%2F%282a%29+%2B+sqrt%28+b%5E2-4%2Aa%2Ac+%29%2F%282%2Aa%29+
x+=+-b%2F%282a%29+-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%2F%282%2Aa%29+
Everything under the square root signs represent how far one root
is in the + direction from -b/2a and equally far the other root is
in the - direction from -b/2a
So, x = -b/2a is the axis of symmetry
-b/2a = -5/(2*1) = -5/2
x = -5/2 answer