Question 579893
y-x=3x
add x to both sides
y= 4x


2(x+y)=14-y

substitute y

2(x+4x)=14+3x

10x=14+3x

add -3x to both sides
7x=14
/7
x=2
when x =2 y = 4x = 4*2=8

(2,8)