For this case we have the following system of equations:

To solve, we clear "x" from the second equation:

We substitute "x" in the first equation:

We clear the value of the variable "y":

We look for the value of the variable "x":

Thus, the solution of the system is given by:

Answer:

Option D
Answer:
24
Step-by-step explanation:
there are 6 seats and 3 boys, 3 girls.
First seat can be given to either boy or a girl.
So there are two ways.
If a boy is selected say, then he has to occupy 3rd and 5th only.
There are 2 ways
Now available positions are 2nd, 4th and 6th, in this girls can be arranged in 3! ways = 6
So total number of ways =

Just break it down into simple numbers
⓵
-4ỿ = 8
Simplify the left side in order to isolate the ỿ!
-4ỿ = 8
+4 +4
Ỿ = 12
⓶
× + 3y - 3z = -26
Simplify the left side in order to isolate the ×, ỿ and z!
× + 3y - 3z = -26
÷3 ÷3
× + ỿ - 3z = -8,66 periodic
÷-3 ÷-3
× + ỿ + z = 2,88 periodic
⓷
2× - 5ỿ + z = 19
Simplify the left side in order to isolate the ×, ỿ and z!
2× - 5ỿ + z = 19
÷2 ÷2
× - 5ỿ + z = 9,5
÷-5 ÷-5
× + ỿ + z = -1,9
17 + 2 = 19 km is 1/2 of the total length, that is,
19 = (1/2)h
(1/2)h = 19 multiply both sides by 2
h = 2*19
h = 38 km
The total length in kilometers is 38 km