
parabola HW help plz
A, write an equation whose graph is a parabola whose vertex is (3/4,3)
B, write an equation whose graph is a parabola that opens downward and has an axis of symmetry x=4
C, Write an equation whose graph is a parabola opens upward and has a yintercept of 1/2
D, Write an equation whose graph is a parabola whose vertex is (3,4) with a y intercept of 1

OK here is what you do
A. the equation for a parabola with vertex $\displaystyle (h,k)$...is $\displaystyle y=a(xh)^2+k$...so for $\displaystyle \frac{3}{4},3)$...is $\displaystyle y=\bigg(x\frac{3}{4}\bigg)^23$
B.the equation for a line facing down with its axis of symmetry at 4 is $\displaystyle y=a(x+4)^2+k$
C.one of the possibilities $\displaystyle y=x^2\frac{1}{2}$
D.to do this you need to set up your equation [tex]y=a(x+3)^2+4...I know...now all you have to do is say is put in your values $\displaystyle 1=a(0+3)^2+4$ and solve for a...so you get $\displaystyle a=\frac{1}{3}$...so your equation is $\displaystyle y=\frac{(x+3)^2}{3}+4$