The equation of a circle is written as ( x-h)^2 + (y-k)^2 = r^2
h and k is the center point of the circle and r is the radius.
In the given equation (x+3)^2 + (y-1)^2 = 81
h = -3
k = 1
r^2 = 81
Take the square root of both sides:
r = 9
The center is (-3,1) and the radius is 9
Answer:
218 students purchased tickets at the dance.
Step-by-step explanation:
Let,
x be the number of presale tickets
y be the number of tickets sold at the dance
According to given statement;
x+y=334 Eqn 1
18x+24y=7320 Eqn 2
Multiplying Eqn 1 by 18
18(x+y=334)
18x+18y=6012 Eqn 3
Subtracting Eqn 3 from Eqn 2
(18x+24y)-(18x+18y)=7320-6012
18x+24y-18x-18y=1308
6y=1308

Therefore,
218 students purchased tickets at the dance.
“Above the door” is the prepositional phrase but I can’t help you you it’s the second part, sorry.
Answer:
20 mph and 4 mph
Step-by-step explanation:
GIVEN: A boat travels upstream for
miles in
hours and returns in
hours traveling downstream in a river.
TO FIND: What is the rate of the boat in still water and the rate of the current.
SOLUTION:
Let the speed of boat in still water be
and speed of current be
.
speed of water in upstream 
speed of water in downstream 
As 


Solving both we get


Hence speed of boat in still water and rate of current is 20mph and 4mph respectively.