1式乘以2得 4x + 6y = 12
2式乘以3得 9x + 6y = -3
相减得5x = -15
x = -3
带回去解得y = 4 1式乘以2得 4x + 6y = 12
2式乘以3得 9x + 6y = -3
相减得5x = -15
x = -3
带回去解得y = 4