# algebra

posted by
**Marissa**
.

1)Write an equation for the parabola with focus (1,3)and vertex(0,3)

answer= x= 1/4(y-3)^2

2)Write an equation for a circle if the endpoints of a diameter are at (1,1)and(1,-9)

answer= (x-1)^2+(y+4)^2=25

3)Which is the equation of a circle with center (0,1)and radius 2 units?

answer= x^2+y^2-2y=4

1) correct for the vertex but I don't know about the focus

2) wrong ( I again plugged your equation into my calculator and I didn't get the diameter as what was given)

3) correct

what do you mean?

for number 2

A.(x-1)^2+(y+4)^2=5

C.(x+1)^2+(y-4)^2=5

D.(x+1)^2+(y-4)^2=25

is it A?

number 1

A.y=(x-4)^2-15

B.y=4(x-1)^2+5

C.y=4(x-1)^2-3

Checking again..2 is fine

I was looking on the wrong side of the circle for the diameter points.