.
You may express x from the first equation and substitute it then to the second equation.
It is how the SUBSTITUTION method works in this case.
You also can subtract the second equation from the first.
It is how the ELIMINATION method works in this problem.
Select any of these two methods and do the rest on your ow.
If you still have questions, let me know (by referring to the problem's ID number 1157077).
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If you need some introductory guidance on solving system of equations, you will find it in the lessons
- Solution of the linear system of two equations in two unknowns by the Substitution method
- Solution of the linear system of two equations in two unknowns by the Elimination method
in this site.