Answer:
(3,-3)
but there are infinately many more.
Explanation:
We need to find a pair of numbers that when substituted in 2x-y we get 9.
because this equation is linear there are actually an infinite number of solutions. So all we have to to is pick a random number for x, say 3, and there will only be 1 value of y that will satisfy the equation, so we just plug it in.
let x =3
2x - y = 9 ⇒ 2×3 - y = 9
⇒ 6 -y = 9
⇒ -y = 3
⇒ y = -3
so (3,-3) is a solution