Answer:
(A)  with
 with  .
.
(B)  with
 with 
(C)  with
 with 
(D)  with
 with  ,
,
Step-by-step explanation
(A) We can see this as separation of variables or just a linear ODE of first grade, then  . With this answer we see that the set of solutions of the ODE form a vector space over, where vectors are of the form
. With this answer we see that the set of solutions of the ODE form a vector space over, where vectors are of the form  with
 with  real.
 real. 
(B) Proceeding and the previous item, we obtain  . Which is not a vector space with the usual operations (this is because
. Which is not a vector space with the usual operations (this is because  ), in other words, if you sum two solutions you don't obtain a solution.
), in other words, if you sum two solutions you don't obtain a solution.
(C) This is a linear ODE of second grade, then if we set  and we obtain the characteristic equation
 and we obtain the characteristic equation  and then the general solution is
 and then the general solution is  with
 with  , and as in the first items the set of solutions form a vector space.
, and as in the first items the set of solutions form a vector space. 
(D) Using C, let be  we obtain that it must satisfies
 we obtain that it must satisfies  and then the general solution is
 and then the general solution is  with
 with  , and as in (B) the set of solutions does not form a vector space (same reason! as in (B)).
, and as in (B) the set of solutions does not form a vector space (same reason! as in (B)).  
 
        
             
        
        
        
Answer:
the answer is 140
Step-by-step explanation:
 
        
                    
             
        
        
        
Answer: joe
Step-by-step explanation:
 
        
             
        
        
        
Answer:
24
Step-by-step explanation:
40/1 * 3/5 = 120/5 
120/5 simplified = 24