2y - x = 5
x^2 + y^2 - 25 = 0
x = 2y - 5
(2y-5)^2 + y^2 - 25 = 0
(2y-5)(2y-5) + y^2 - 25 = 0
4y^2 - 20y + 25 + y^2 - 25 = 0
5y^2 - 20y = 0
y = 0 , y = 4
x = 2y - 5 , when y = 0
x = - 5
x = 2y - 5 , when y = 4
x = 8 - 5
x = 3
        
             
        
        
        
Answer:
I don't know
Step-by-step explanation:
 
        
                    
             
        
        
        
If is an integer (a whole number), then the expression represents an even number, because even numbers are the multiples of 2. The expressions 2 n − 1 and 2 n + 1 can represent odd numbers, as an odd number is one less, or one more than an even number.
        
             
        
        
        
45 hours.
80 - 70= 10, and 450/10 is 45.
to justify, you can do 70x45= 3,150, and 80x45= (3,600 - 3,150= 450)