You could produce a pair of like terms with opposite coefficients by multiplying the first equation by what number? 6
If you multiply the first equation by 6, the following system is the result.

3x + 9y = -42
-3x + 2y = -2

To solve this system by elimination,
✔ add
the equations.
The solution to the system is

(
1/2
⇒ -2,
5
⇒ -4)