Question

how do i find the y intercept of a parabola such as y=x^2+2x

Answer 1

make x=0

Answer 2

c =0

Answer 3

?
you were no help

Answer 4

any equasion?

Answer 5

x=0 to find y-intercept
y=0^2+2(0)
y-intercept at (0,0)

Answer 6

is that always the case where u plug in 0 for x?

Answer 7

yes

Answer 8

so there is a point on the parabola at 0,0

Answer 9

sure is

Answer 10

that's the vertex luis, quite different from the y-intercept

Answer 11

what would be the axis of symetry for this problem?

Answer 12

y=x^2+2x
h = -2/2 = -1
->k = (-1)^2 - 2 = -1

Answer 13

what? any formula?

Answer 14

-b/(2a) = -2/2=-1, x=-1, or you can complete the square as luis did. the axis of symmetry is the vertical line that goes through the x-coordinate of the vertex

Answer 15

haha thanks though im a little confused about the vertex

Answer 16

or highest if its maximum right?

Answer 17

it will be a maximum if a<0 in ax^2+bx+c