9th. algebra
posted by sc .
how can I figure out the formula. example. I need to transform the following equation y = x2 + 4  8 into vertex form and then I need to state the coordinates of the vertex of the parabola. I forgot how to arrive at the answer

I will assume there is a typo and you meant
y = x^2 + 4x  8
take 1/2 the coefficient of the x term, square it, then add and then subtract it
( 1/2 of 4 is 2 and then squared would be 4)
y = x^2 + 4x + 4  4  8
the first three terms are now a perfect square
y = (x+2)^2  12
compare this with
y = a(xp)^2 + q which has vertex (p,q) and you can conclude that the vertex of
y = (x+2)^2  12 is (2,12)