For this case we have the following system of equations:
[tex]y = 3x-7\\6x + 3y = 15[/tex]
To find the solution, we follow the steps below:
We substitute the first equation in the second equation:
[tex]6x + 3 (3x-7) = 15\\6x + 9x-21 = 15\\15x = 15 + 21\\15x = 36\\x = \frac {36} {15}\\x = \frac {12} {5}[/tex]
Now, we find the value of "y":
[tex]y = 3 (\frac {12} {5}) - 7\\y = \frac {36} {5} -7\\y = \frac {36-35} {5}\\y = \frac {1} {5}[/tex]
Thus, the solution of the system is:
[tex](x, y): (\frac {12} {5}, \frac {1} {5})[/tex]
Answer:
The value of the variable "y" is [tex]\frac {1} {5}[/tex]