If you're talking about #3, then the equation would be 10+12.50h=5+15h. 
h will equal 2, and the cost for that number of hours would then be $35.
 
        
        
        
Answer:
x ∉ R
Step-by-step explanation:
x² = - 21
if x² < 0 => x ∉ R
 
        
             
        
        
        
Answer:5 * (1/2 * 6 * 14)= x
Step-by-step explanation: :D