Completing the Square?

Question

Change y = x^2 + 14x -14 to standard form by completing the square.

The equation of the axis of symmetry is x =____

Answer 1

x^2 +14x ______= 14
you divide the middle coeffecient (the 'x' term) by 2 and square it, so you divide 14 by 2 and get 7 and square it, and get 49. so you have:
x^2 +14x + 49= 14+49
you have to add the 49 to other side too!
the nber you got when you divided by two is what you use for the compacted square:
(x+7)^2= 63
so,
y= (x+7)^2 - 63

hope that helps!

Answer 2

To complete the square, divide the coefficient of x by two and put (x + this coefficient)^2
In this case it will be (x+7)^2. to get the -14 you then square seven, and work out what number to add or minus to that to get -14, in this case -63.
so the answer is (x+7)^2 - 63.

Answer 3

y = (x² + 14x + 49) - 49 - 14
y = (x + 7)² - 63
Axis of symmetry is x = - 7