Đáp án:

Giải thích các bước giải:

 TA có:
`a)(x+1)/65 + (x+3)/63=(x+5)/61+(x+7)/59`

`(x+1)/65 + (x+3)/63-(x+5)/61-(x+7)/59=0`

`((x+1)/65+1) + (x+3)/63+1)-(x+5)/61+1)-(x+7)/59+1)=0+1+1-1-1`

`(x+66)/65 + (x+66)/63-(x+66)/61-(x+66)/59=0`

`(x+66) . (1/65 +1/63-1/61-1/59)=0`

Vì `1/65 +1/63-1/61-1/59 ne 0` nên:

`=>x+66=0`

`=>x=0-66

`=>x=-66`

Vậy `x=-66`

`----`

`b)(315-x)/101+(313-x)/103+(311-x)/105=-3`

`((315-x)/101+1)+((313-x)/103+1)+((311-x)/105+1)=0`

`(416-x)/101+(416-x)/103+(416-x)/105=0`

`(416-x).(1/101+1/103+1/105)=0`

Vì `1/101+1/103+1/105 ne 0` nên:

`=>416-x=0`

`=>x=416-0`

`=>x=416`

Vậy `x=416`

`-----`

`c)3(x-1)+2(x+5)=x-4`

`3x-3+2x+10=x-4`

`5x+7=x-4`

`=>5x-x=-7-4`

`=>4x=-11`

`=>x=-11:4`

`=>x=-11/4`

Vậy `x=-11/4`

`d)2/3.(3x+1/2)-2.(2x-1/2)=-1 1/3`

`=>2/3. 3x+2/3 . 1/2-2. 2x-2. 1/2=-1 1/3`

`=>2x+1/3-4x+1=-4/3`

`=>-2x+4/3=-4/3`

`=>-2x=-4/3-4/3`

`=>-2x=-8/3`

`=>x=-8/3:(-2)`

`=>x=4/3`

Vậy `x=4/3`