Option C: 2x + 3y = 7; 4x + 6y = 5
Substituting the first equation into the second equation, we get: 4(2x + 3y) + 6y = 5
Expanding the left side gives: 8x + 12y + 6y = 5
Combining like terms gives: 8x + 18y = 5
Subtracting 5 from both sides gives: 8x + 18y - 5 = 0
Combining like terms gives: 8x + 18y = -5
This equation represents a line in the xy-plane. The original equation 2x + 3y = 7 represents a different line in the xy-plane. These lines do not intersect, so this system of equations has no solutions and is inconsistent.