You gave the corresponding directrix as just "y". You have to give an equation, not just "y". I will guess arbitrarily that you meant "y=2". If you meant another number, then the principle will be the same. distance from any pt. (x,y) to focus) eccentricity = ------------------------------------------- distance from that pt. (x,y) to directrix) Distance from (x,y) to focus (1,-3) =Distance from (x,y) to the point (x,2) on the directrix = = = |y-2| Use the eccentricity formula above: = Square both sides: = Cross-multiply: 9(y - 2)² = 4[(x - 1)² + (y + 3)²] 9(y² - 4y + 4) = 4(x - 1)² + 4(y + 3)² 9y² - 36y + 36 = 4(x - 1)² + 4(y² + 6y + 9) 9y² - 36y + 36 = 4(x - 1)² + 4y² +24y + 36 5y² - 60y - 4(x - 1)² = 0 Factor out 5 from the first two terms: 5(y² - 60y) - 4(x - 1)² = 0 Complete the square in the first parentheses: -60× = -30, the (-30)² = 900. Add 900 in the parentheses and since the parentheses has coefficient 5 we add 5·900 or 4500 on the right: 5(y² - 60y + 900) - 4(x - 1)² = 0 + 4500 5(y - 30)² - 4(x - 1)² = 4500 Get a 1 on the right by dividing through by 4500: - = 1 - = 1 Edwin