Question

Solve following x-y=2 5x+3y=18

Answer 1

$x-y=2 \\ -x\ \ -x \\ -y=-x+2 \\ y=x-2 \\ \\ 5x+3(x-2)=18 \\ 5x+3x-6=18 \\ 8x-6=18 \\ +6\ \ \ \ +6 \\ 8x=24 \\ /8\ \ \ /8 \\ x=3$

Answer 2

X-y = 2
5x+3y =18 

let do some plug and play 

x-y = 2 
x = 2+y
now we got an answer for x lets plug that in the other equation

5(2+y) + 3y = 18
10+5y + 3y = 18
10 + 8y = 18
8y = 8
y = 1 

now lets find x 
x = 2 +y 

x = 2+ 1 
x = 3.