Đáp án + Giải thích các bước giải:
`1.` `-5/2:(3/4-1/2)`
`=-5/2:(3/4-2/4)`
`=-5/2:1/4=-5/2*4=-10`
`2.` `298/719:(1/4+1/12-1/3)`
`=298/719:(3/12+1/12-4/12)`
`=298/719:0` ( vô lý, không thể tính được vì mẫu phải khác `0` )
`3.` `(27*18+27*103-120*27)/(15*33+33*12)`
`=[27(18+103-120)]/[33(15+12)]`
`=(27*1)/(33*27)=1/33`
`4.` `(x-5/8)*5/18=-15/36`
`=>(x-5/8)*5/18=-5/12`
`=>x-5/8=-5/12:5/18`
`=>x-5/8=-5/12*18/5`
`=>x-5/8=-3/2`
`=>x=-3/2+5/8`
`=>x=-12/8+5/8=-7/8`
Vậy `x = -7/8`
`5.` `|x-1/3|=5/6`
`=>`\(\left[ \begin{array}{l}x-\dfrac{1}{3}=\dfrac{5}{6}\\x-\dfrac{1}{3}=-\dfrac{5}{6}\end{array} \right.\)
`=>`\(\left[ \begin{array}{l}x=\dfrac{7}{6}\\x=-\dfrac{1}{2}\end{array} \right.\)
Vậy `x in {7/6;-1/2}`.
