Đáp án: c) -1
d) x = `-5/18`
Giải thích các bước giải:
c) `-7/11` . `11/19` + `-7/11` . `8/19` + `-4/11` = `-7/11`.(`11/19` + `8/19`) + `-4/11` = `-7/11` . 1 + `-4/11` = `-11/11` = -1
d) (x - `7/18`). `18/29` = `-12/29`
`<=>` `18/29`x - `18/29`. `7/18` + `12/29` = 0
`<=>` `18/29`x - `7/29` + `12/29` = 0
`<=>` `18/29`x = `-5/29`
`<=>` x = `-5/18`