2 câu trả lời
Đáp án:
Giải thích các bước giải:
$$\eqalign{ & {9 \over 2} - \left[ {{2 \over 3} - \left( {x - {7 \over 4}} \right)} \right] = - {5 \over 4} \cr & \Leftrightarrow {2 \over 3} - \left( {x - {7 \over 4}} \right) = {9 \over 2} + {5 \over 4} \cr & \Leftrightarrow {2 \over 3} - \left( {x - {7 \over 4}} \right) = {{18 + 5} \over 4} \cr & \Leftrightarrow {2 \over 3} - \left( {x - {7 \over 4}} \right) = {{23} \over 4} \cr & \Leftrightarrow x - {7 \over 4} = {2 \over 3} - {{23} \over 4} \cr & \Leftrightarrow x - {7 \over 4} = {{8 - 69} \over {12}} \cr & \Leftrightarrow x - {7 \over 4} = - {{61} \over {12}} \cr & \Leftrightarrow x = {7 \over 4} - {{61} \over {12}} \cr & \Leftrightarrow x = {{21 - 61} \over {12}} \cr & \Leftrightarrow x = {{ - 40} \over {12}} = {{ - 10} \over 3} \cr} $$
`9/2-[2/3-(x-7/4)]=-5/4`
`->2/3-(x-7/4)=9/2-(-5/4)`
`->2/3-(x-7/4)=9/2+5/4`
`->2/3-(x-7/4)=36/8+10/8`
`->2/3-(x-7/4)=(36+10)/8`
`->2/3-(x-7/4)=46/8`
`->2/3-(x-7/4)=23/4`
`->x-7/4=2/3-23/4`
`->x-7/4=8/12-69/12`
`->x-7/4=(8-69)/12`
`->x-7/4=(-61)/12`
`->x=(-61)/12+7/4`
`->x=(-61)/12+21/12`
`->x=((-61)+21)/12`
`->x=(-40)/12`
`->x=(-10)/3`
Vậy `x=(-10)/3`
