I hope this helps you
x=5+y
5 (5+y)+2y= 4
25+5y+2y=4
7y= -21
y= -3
x=5+y
x=5-3 x= 2
Answer: a=2/5b + 1/5c (I may have answered your question but idk if I did)
Step 1: Add -4a to both sides.
9a−2b+−4a=4a+c+−4a
5a−2b=c
Step 2: Add 2b to both sides.
5a−2b+2b=c+2b
5a=2b+c
Step 3: Divide both sides by 5.
5a/5=2b+c/5
a=2/5b+1/5c