algebra (parabolas)
posted by Bri on .
tell whether the graph opens upward or downward. then find the axis of symmetry and vertex of the graph of the function
1. y=xsquared5
2. y=2*xsquared+6x+7

x^2 = (y + 5)
when x gets big, y gets big, opens up (holds water)
symmetric about y axis (x = 0)
vertex at (0,5)
2 x^2  6 x =  y + 7
x^2  3 x = (1/2)y + 7/2
add (3/2)^2 = 9/4 to both sides
x^2 3 x +9/4 = (2/4)y + 23/4
(x3/2)^2 = (1/4)(2y23)
axis at x = 3/2
vertex at (3/2 , 23/2)
when x gets big, y gets big negative. Opens down (sheds water)