Algebra-1

Question Analysis
This question tests the student's ability to use the substitution method to solve a system of equations. The student needs to solve one equation for one variable and then substitute that expression into the other equation.

Key Concept Explanation
The key concept here is the substitution method, which involves solving one equation for one variable and substituting that expression into the other equation to eliminate one variable and solve for the other.

Step-by-step Solution
1. Solve the second equation for : .
2. Substitute into the first equation :