To use the elimination method, the coefficient of one variable in one equation must be the opposite number of the coefficient of the same variable in the second equation.
Here you can multiply the first equation by 2, and the second equation by -3.
Now you just add the equations by sides and solve for one variable.
Now you solve for the other variable by substituting -7 for x in one of the equations.
You could choose x at the beginning as well. Then you'd have: