{x+y=27, (1)
{y+z=33, (2)
{z+x=30 (3)
(1)+(2)+(3)得2x+2y+2z=90 (4)
(4)÷2得 x+y+z=45 (5)
(5)-(1)得z=18
(5)-(2)得x=12
(5)-(3)得y=15
三元一次方程组的解为
{x=12
{y=15
{z=18
祝你好运
{x+y=27, (1)
{y+z=33, (2)
{z+x=30 (3)
(1)+(2)+(3)得2x+2y+2z=90 (4)
(4)÷2得 x+y+z=45 (5)
(5)-(1)得z=18
(5)-(2)得x=12
(5)-(3)得y=15
三元一次方程组的解为
{x=12
{y=15
{z=18
祝你好运