Part B.
Find the equation of the directrix of the parabola found in part A.

hope it may help you

Step-by-step explanation:

★Question★

The sum of a square of a number and one less than the number, equals nine less than, the square of one more than the same number. Find the number.

★Answer★

Let the number be 'x'.

Atq,

=> x² +x-1=(x+1)²-9

=>x²+x-1=x²+1+2x-9

=>x²-x²+x-2x-1-1+9=0.

=>x-7=0

.°. x =7.