解方程:X+y+z=3.3 X/3+Y/4+Z/5=51/60 X/5+Y/4+Z/3=53.4/60

题目

解方程:X+y+z=3.3 X/3+Y/4+Z/5=51/60 X/5+Y/4+Z/3=53.4/60
X+y+z=3.3 (1)
X/3+Y/4+Z/5=51/60 (2)
X/5+Y/4+Z/3=53.4/60 (3)

答案

无非是化简
去分母得到方程组x+y+z=3.3(1)
20x+15y+12z=51(2)
12x+15y+20z=53.4(3)
(1)*20-(2)
(1)*12-(3)
得到两元一次方程组解得到y=0.6 z=1.5
最后得x＝1.2