Answer:

Step-by-step explanation:
Since the vertex is right between the vertex and the directrix, the y value of the vertex must be (3+(-1))/2=1. The x coordinate will just be the same as that of the focus, or in this case 0. This means that the vertex will be at (0,1). Since the graph opens toward the focus, it will be opening up, and since its vertex is at (0,1), it will have an equation of:

Hope this helps!
Answer:
x = 7
Step-by-step explanation:
Add 12 to both sides:
2x + 9 = 5x - 12
2x + 21 = 5x
Subtract 2x from both sides:
21 = 3x
Divide each side by 3:
7 = x
So, x = 7
I am guessing there is half of each type of book, so there are 50/100 or 1/2 that are fiction
hope this helped
Answer:

Step-by-step explanation:
The upside down exclamation point(¡) denotes the subfactorial in math. There are two ways to approach solving the subfactorial, one being exact, while the other is a more practical approach.
One way (the mathematically correct way) is using the formula:
n=n!∑[(-1)^k]/k!, where k starts at 0 and counts to n.
However, another, less accurate way is simply ¡n = [n!/e], where the brackets mean to round to the nearest integer, which returns 2.25268983 * 10^(103)
Hope it helps :) and let me know if you want me to elaborate, or if the notation used was intended to be something else, as the subfactorial of 72 seems like an unnecessary amount of tedium.
Your answer is the last option
54-6i/41