18X+3Y+3Z=57 14x+5y+5z=47求X Y Z的值 13x+5y+6z=41

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18X+3Y+3Z=57 14x+5y+5z=47求X Y Z的值 13x+5y+6z=41

18X+3Y+3Z=57 14x+5y+5z=47求X Y Z的值 13x+5y+6z=41
18X+3Y+3Z=57 14x+5y+5z=47求X Y Z的值 13x+5y+6z=41

18X+3Y+3Z=57 14x+5y+5z=47求X Y Z的值 13x+5y+6z=41
18X+3Y+3Z=57 (1)
14x+5y+5z=47 (2)
13x+5y+6z=41 (3)
(2)-(3):
x-z=6 x=6+z
(1)*5-(3)*3:
90x+15y+15z-39x-15y-18z=57*5-41*3
51x-3z=162 x=6+z
51(6+z)-3z=162
51*6+51z-3z=162
51*6-162=-48z
z=-3
x=6+z=3
代入,(1):
18*3+3y+3*(-3)=57
3y=57-54+9
y=4
所以:
x=3
y=4
z=-3