Answer:
35
Step-by-step explanation:
0.25 x 140 = 35
 
        
             
        
        
        
Corresponding sides have the same ratio, so
  x/15 = 12/(12+8) = 3/5
  x = 15*3/5
  x = 9
        
             
        
        
        
The solution depends on the value of 

. To make things simple, assume 

. The homogeneous part of the equation is

and has characteristic equation

which admits the characteristic solution 

.
For the solution to the nonhomogeneous equation, a reasonable guess for the particular solution might be 

. Then

So you have


This means


and so the general solution would be
 
 
        
        
        
Answer:
Step-by-step explanation:
Estimating a sum by rounding to get the best estimate is the goal of this lesson. Notice that we try to estimate. We don't need to have an exact answer!
Notice that for numbers with two digits, there can only be one estimate because you can only round to the tens place.
Estimate the following sums: 36 + 21, 74 + 15, and 85 + 24
36 + 21 = 40 + 20 = 60
74 + 15 = 70 + 20 = 90