Expert: Sherry Wallin - 4/14/2009

Question
Hello im a homeschool parent and I really need ur help with this I have no clue wat to do please help and answer god bless

Determine how the following parabolas open. Answer A if it opens to the right, B if it opens to the left, C if it opens up, and D if it opens down
             1
1.  x = - -------y^2
             12

            1
2.  y = ----- x^2
           4

               1
3. y = - ---------- x^2
               8


4. x= 1/20  y^2

5. y= - 1/28  x^2

6. x^2 = 24y

7. y^2 = -12x

8. x = y^2 + 1

9. y = x^2 - 3

10. x^2 = -y + 2

Find the focus and the directrix of the following parabolas

11. y = - 1/8 x^2

12. y = - 1/28 x^2

13. x = - 1/12 y^2

14. y = 1/4 x^2

15. y^2 = - 12x

Answer
Any parabola with y = to something will open up if x is positive and down if x is negative. Likewise if the equation is x = to something it will open to the right if y is positive and to the left if y is negative
so

1 opens to the left
2 opens  up
3 opens down
4 opens to the right
5 opens to the left
6 opens up
7 opens left
8 opens to right
9 opens up
10 opens down

Math Prof