Answer:
4
Step-by-step explanation:
y-7=21
+7 +7
y=21+7
y=28
6/7 of 1 3/4......turn the mixed number to an improper fraction...and " of " means multiply
6/7 * 7/4 = 42/28 = 1 1/2...so a compact car weighs 1 1/2 tons or 1.5 tons
Take the homogeneous part and find the roots to the characteristic equation:

This means the characteristic solution is

.
Since the characteristic solution already contains both functions on the RHS of the ODE, you could try finding a solution via the method of undetermined coefficients of the form

. Finding the second derivative involves quite a few applications of the product rule, so I'll resort to a different method via variation of parameters.
With

and

, you're looking for a particular solution of the form

. The functions

satisfy


where

is the Wronskian determinant of the two characteristic solutions.

So you have




So you end up with a solution

but since

is already accounted for in the characteristic solution, the particular solution is then

so that the general solution is
Step-by-step explanation:
7x+5y=25 ×3 7×-1.5+5y=25
5x+3y= -23 ×5 -10.5 +5y =25
5y= 25 + 10.5
21x+15y=75 5y= 35.5
25x+15y=69 y= 7.1
-4x=6
x=-1.5
Answer:
The answer is 15
Step-by-step explanation:
hope this helps