练习1：基础求解 14.5
Python
# 测试用例1：有唯一解
# 2x + 3y = 7
# 4x - y = 3
# 解：x = 1, y = 1
# 测试用例2：无解
# 2x + 3y = 7
# 4x + 6y = 10
# 测试用例3：无穷多解
# 2x + 3y = 6
# 4x + 6y = 12
