Помогите с дз -7x-(x+4) 19x-3y-4x+12y -7-x+6 N+8(5n-9)

Question

Помогите с дз
-7x-(x+4)
19x-3y-4x+12y
-7-x+6
N+8(5n-9)

Answer 1

-7х-х-4=0
-8х=4
х=4/-8
х=-1/2 
х=-0,5

19х-4х-3у+12у=0
15х+9у=0

-7-х+6=0
-х=7-6
х=-1

n+40n-72=0
41n-72=0
41n=72
n=72/41
n=1 31/41