Two planes that intersect are simply called a plane to plane intersection. When they intersect, the intersection point is simply called a line.
Therefore, Plane R and Plane S form a line when they intersect.
<span>x = 5 i beliavie :)..............................</span>
The standard equation of a circle is:

where (h,k) is the center and r is the radius.
We need to make an equation of a circle, whose center is (11,-5) with any radius. Therefore, substitute the value.

The bolded part is your answer. Since the radius is not given, we can put any value.
Answer:
x= 10, x=1
Step-by-step explanation:
(x-1)(x-10)=0
then solve for x
1.
If no changes are made, the school has a revenue of :
625*400$/student=250,000$
2.
Assume that the school decides to reduce n*20$.
This means that there will be an increase of 50n students.
Thus there are 625 + 50n students, each paying 400-20n dollars.
The revenue is:
(625 + 50n)*(400-20n)=12.5(50+n)*20(20-n)=250(n+50)(20-n)
3.
check the options that we have,
a fee of $380 means that n=1, thus
250(n+50)(20-n)=250(1+50)(20-1)=242,250 ($)
a fee of $320 means that n=4, thus
250(n+50)(20-n)=250(4+50)(20-4)=216,000 ($)
the other options cannot be considered since neither 400-275, nor 400-325 are multiples of 20.
Conclusion, neither of the possible choices should be applied, since they will reduce the revenue.