Answer:
-18
Step-by-step explanation:
Left Hand Side = -2(7a + 9b) = -14a - 18b
Comparing it with Right Hand Side, ? = -18
Answer:
m ≠1 ( all m in R except 1 )
Step-by-step explanation:
hello :
mx − y + 3 = 0.....(*)
(2m − 1)x − y + 4 = 0 ....(**)
multiply (*) by : -1 you have : -mx+y-3=0 ....(***)
(2m − 1)x − y + 4 = 0 ....(**)
add(***) and(**) : -mx+ (2m − 1)x+1 =0
(2m-m-1)x+1=0
(m-1)x = -1
this system have no solution if : m-1≠0 means : m ≠1
1700 because I multiply 30 x 20 then 20 x 5 then 30 x 5 then add them all up and multiply your answer by 2
Answer:
Therefore the concentration of salt in the incoming brine is 1.73 g/L.
Step-by-step explanation:
Here the amount of incoming and outgoing of water are equal. Then the amount of water in the tank remain same = 10 liters.
Let the concentration of salt be a gram/L
Let the amount salt in the tank at any time t be Q(t).

Incoming rate = (a g/L)×(1 L/min)
=a g/min
The concentration of salt in the tank at any time t is =
g/L
Outgoing rate =



Integrating both sides

[ where c arbitrary constant]
Initial condition when t= 20 , Q(t)= 15 gram


Therefore ,
.......(1)
In the starting time t=0 and Q(t)=0
Putting t=0 and Q(t)=0 in equation (1) we get









Therefore the concentration of salt in the incoming brine is 1.73 g/L
Before the mechanic worked on it, it cost .09 (cents) per mile. After the mechanic worked on it, it cost .08 (cents) per mile. Divide the number of gallons by the miles in each case and multiply the result by 4.