Answer:d
Step-by-step explanation:
16-4=12 and 16+4=20
First look for the fundamental solutions by solving the homogeneous version of the ODE:

The characteristic equation is

with roots
and
, giving the two solutions
and
.
For the non-homogeneous version, you can exploit the superposition principle and consider one term from the right side at a time.

Assume the ansatz solution,



(You could include a constant term <em>f</em> here, but it would get absorbed by the first solution
anyway.)
Substitute these into the ODE:




is already accounted for, so assume an ansatz of the form



Substitute into the ODE:





Assume an ansatz solution



Substitute into the ODE:



So, the general solution of the original ODE is

Answer:age of the man: 75 age of the woman:25
Step-by-step explanation:
First, We need to define the variables
x: age of the man
y: age of the woman
at the first time he has three times her age
x=3y (1)
in 25 years time
(x+25)=2(y+25) (2)
we clear the equation
X+25=2y+50
X=2y+25
we substitute in the (1) equation:
2y+25=3y
y=25
x=3*25=75