Help. ​

2x + 3y   = 11    →  3y  = 11 - 2x        (1)

3x + 3y   = 18      (2)

Put (1) into (2)    and we have

3x  + 11 - 2x  =  18        subtract  11 from both sides and simplify

x =  7          and using  (2)  to find y, we have that

3 (7)  + 3y  = 18

21  + 3y = 18     subtract 21 from both sides

3y   =  - 3       divide both sides by 3

y  =  -1