Question

Write the equation of a parabola with a vertex and (-5, 2) and a directrix y = -1

Answer 1

y=(x+5)²/6 + 1/3

Explanation:

Use the distance formula to plug in the values you know:

√(y+1)² =√(x+5)² +( y-2)²

the square roots cancel out

(y+1) ²= (x+5)² +(y-2)²

(y+1) (y-1)= (x+5)² + (y-2) (y-2)

y²+2y+1= (x+5)² + y² -4y+4

the y² cancel out

2y+ 4y = (x+5)² + 4-1

6y= (x+5)² +3

y= (x+5)² /6+ 1/3