Answer:
-3(4+2n) multiply -3 by 4 and 2n
-12-6n
You just have to add one eqaution to another :
-x + x -y + 2y = 7 + 7
y = 14
Then apply y = 14 to one of the equations :
eg: x + 2(14) = 7
x + 28 = 7
x = - 21
The awnser is x= -21 y= 14
I hope i awnsered your question
your answer is adjacent angles