Answer:
(4)and (7)
Step-by-step explanation:
A parabola has a focus of F(2,8.5) and a directrix of y=9.5. The point P(x,y) represents any point on the parabola, while D(x,9.5) represents any point on the directrix.
Now, Step 1: FP=DP, using the distance formula,
Step 2: [tex]\sqrt{(y-8.5)^{2}+(x-2)^{2}}=\sqrt{(y-9.5)^{2}+(x-x)^{2}}[/tex]
Step 3: Solving the step 2,we get
[tex]\sqrt{(y-8.5)^{2}+(x-2)^{2}}=\sqrt{(y-9.5)^{2} }[/tex]
Squaring on both sides and then solving, we get
[tex]x^{2}-4x+4+y^{2}-17y+72.25=y^{2}-19y+90.25[/tex]
Step 4: [tex]x^{2}-4x-14=-2y[/tex]
Step 5: Finding the value of y by dividing both sides by -2, we get
[tex]\frac{x^{2}-4x-14}{-2}=y[/tex]
Thus, Step 4 and 5 is incorrect because she added the y-terms incorrectly and also the previous step is incorrect on step 4.