Solve the system of equations: x + y = 7, 2x + y = 8

Solution using substitution:

1. From the first equation, express y in terms of x: \( y = 7 - x \).
2. Substitute this expression for y into the second equation: \( 2x + (7 - x) = 8 \).
3. Simplify and solve for x: \( 2x + 7 - x = 8 \) => \( x + 7 = 8 \) => \( x = 1 \).
4. Substitute the value of x back into the expression for y: \( y = 7 - 1 \) => \( y = 6 \).

Answer: x = 1, y = 6