For this case we have the following system of equations:

We multiply the first equation by -4:

We have the following equivalent system of equations:

We add the equations:

We find the value of the variable "x":

Thus, the solution of the system is:

See the graphic in the attached image
ANswer:

See the graphic in the attached image
4=2/7x
(7)4=2/7x(7)
28=2x
— —
2. 2
14=x
x=14
30 = 6 + 2x
x = 12 fish caught last year
(3n)-2=5
Move all numbers without a variable to the right side of the equation
3n=7
Divide 7 by 3
n=2.333