Answer :
Maybe y= -10
because if x was 4 then it would be 20 + 4y
But if y was -10 then (4•-10=-40) and 20+-40= -20
this is just a guess though
because if x was 4 then it would be 20 + 4y
But if y was -10 then (4•-10=-40) and 20+-40= -20
this is just a guess though