Answer:
Step-by-step explanation:
-2x + 2y = -4 (times 3) -6x + 6y = -12
3x + 3y = -18 (times 2) 6x + 6y = -36
.
-6x + 6y = -12
<u>6x + 6y = -36 </u>+
12y = -48
y = -4
.
Substitute the value of y to the one of equations
-2x + 2(-4) = -4
-2x - 8 = -4
-2x = -4 + 8
-2x = 4
x = -2
Answer:
Step-by-step explanation:
For this case the solution flows at a rate of 2L/min and leaves at 1L/min. So then we can conclude the volume is given by
Since the initial volume is 10 L and the volume increase at a rate of 1L/min.
For this case we can define A as the concentration for the salt in the container. And for this case we can set up the following differential equation:
Because at the begin we have a concentration of 8 gr/L and would be decreasing at a rate of
So then we can reorder the differential equation like this:
We find the solution using the integration factor:
And then the solution would be given by:
And if we simplify this we got:
And after do the integral we got:
And using the initial condition t=0 A= 20 we have this:
So then we have this function for the solution of A:
And now replacinf t= 40 we got:
