Answer:
D. y=30x
Step-by-step explanation:
So x represents like say if he mowed 3 yards. 
y=30(3)
Then y would equal 90
 
        
                    
             
        
        
        
Answer:
4x² + 12 = 7x 
4x² + 12 - 7x = 0
use the quadratic formula and get your answer!
Step-by-step explanation:
 
        
             
        
        
        
Answer:
9 hr * 60 min/hr = 540 min. 540 min * 60 sec/min = 32,400 sec. Use the method described by panic mode: round the number down until there is only one non-zero digit left. Here, 32,400 rounds down to 30,000. Now count the number of zeroes; the result is the order of magnitude: 4. (You see this in scientific notation also: 30,000 = 3 × 10^4.)
 
        
             
        
        
        
Answer:
The circumference of a circle is c=3.14r
Step-by-step explanation:
 
        
                    
             
        
        
        
Answer:
2.13 X 104 square acres
Step-by-step explanation:
Divide 6.4 acres by 3 miles = factor of 2.13
Therefore the answer must be 2.13 X 104 square acres