I think is 20 but i am not sure
Answer:

Step-by-step explanation:
The given system of linear equations is:

We have to solve the equations for the values of
.
Let us use elimination method in which we eliminate one of the variables from the two variables.
For this, let us multiply the first equation by
and second equation by 
Now, the equations become:

Now, let us add (1) and (2):

Using the equation:

Putting value of
:

So, the answer to the system of linear equations is:

Answer:
The perpendicular line is:
y = 1/3 x + 2/3
Step-by-step explanation:
The given equation can be reduced to its slope-intercept form as shown below:
3x + 9y = 8y - 2
subtract 8 y from both sides
3 x + y = -2
subtract 3 x from both sides
y = - 3 x -2
therefore we know that the slope of this line is -3, and then, a perpendicular line to it must have slope given by the "opposite of the reciprocal" of this slope. That is, the slope of any perpendicular line to this one must be: 1/3
We use this slope to find the equation of the line passing through the point (13. 5)
y = 1/3 x + b
passing through (13, 5) means:
5 = 1/3 (13) + b
therefore, we can find b from the above equation
b = 5 - 13/3 = 15/3 - 13/3 = 2/3
Then the equation of this perpendicular line is:
y = 1/3 x + 2/3