Aparabola has a focus of f (8.5,-4) and a directrix of x=9.5.
what is the equation of the parabola?
a) 1/2 y² + 4y - 1= x
b) -1/2y²- 4y +1 = x
c) 1/2y²- 4y+1=x
d) -1/2y² + 4y-1=x

Solve the system of equations. y= 2x y= x^2 - 15

This is different from the first one can someone me

Expresa commuter train leaves downtown sation and travels at a average speed of 55 miles per hour towards the north side sation, which is 50miles away. thirty minutes later, express commuter train #7 leaves north side and travels at a average speed of 35miles per hour towards downtown sation. at the moment the two trains pass each other, how far(in miles) is train #12 from the downtown sation and how long(in minutes) has the #12 train been traveling