Answer:
n * r ^2
Step-by-step explanation:
 
        
             
        
        
        
Answer:
x=3 and y=1
Step-by-step explanation:
subtract equation 2 from 1
then (2x+3y) -(2x+y) =9-7
2x-2x+3y-y =2
2y=2 therefore y=1
substitute y value in 2x+y=7
2x+1=7
2x=7-1
2x=6
x=3
 
        
             
        
        
        
Answer:
12 hours
Step-by-step explanation:
Let Theo's siste can paint a fence in x times 
Given.
Theo can paint a fence three times as fast as his sister can. Working together, they can paint a fence in 9 hours.

Apply cross multiplication

Theo’s sister to paint the fence in 12 hours.
 
        
             
        
        
        
Here is the answer I believe. It goes in a x all it did was added to to each x and y (-3,0)