Question

解下列方程（有过程)(1)x:y:z=3:4:52x+3y-5z=-14(2)x/7=y/10=z/52x+3y=44快

Answer 1

(1)因为x:y:z=3:4:5 ,所以x/3=y/4=z/5

得x=3y/4,z=5y/4

将上式代入2x+3y-5z=-14,化简得6y+12y-25y=-56

解得y=8.

即可得x=6,z=10

(2)因为x/7=y/10,所以x=7y/10.

将x=7y/10代入2x+3y=44,

得7y/5＋3y＝44,

两边同时乘于5得,7y+15y＝220,

即22y＝220,y＝10

可得 X＝7,Y＝10 ,Z＝5