Đáp án:
`1)x=416`
`2)(x;y;z)=(-6;-4,5;-4)`
Giải thích các bước giải:
`1)`
`(315-x)/101+(313-x)/103+(311-x)/105+(309-x)/107=-4`
`->(315-x+101)/101+(313-x+103)/103+(311-x+105)/105+(309-x+107)/107=0`
`->(416-x)/101+(416-x)/103+(416-x)/105+(416-x)/107=0`
`->(416-x).(1/101+1/103+1/105+1/107)=0`
`->416-x=0` vì (`1/101+1/103+1/105+1/107\ne0`)
`->x=416`
Vậy `x=416`
`2)`
`x/2=(2y)/3=(3z)/4=k`
`->x=2k;y=(3k)/2;x=(4k)/3`
Ta có: `x.y.z=-108`
`->2k. (3k)/2 . (4k)/3=-108`
`->(24k^3)/6=-108`
`->4k^3=-108`
`->k^3=-27`
`->k^3=(-3)^3`
`->k=-3`
`->x=2k=2.-3=-6`
`->y=(3k)/2=(3.(-3))/2=-9/2=-4,5`
`->z=(4k)/3=(4.(-3))/3=(-12)/3=-4`
Vậy `(x;y;z)=(6;-4,5;-4`
