Đáp án:
$\\$
`P = ( (-1)/2 + 5/23) : 3/7 + (3/2 - 28/23) : 3/7`
`-> P = ( (-1)/2 + 5/23) . 7/3 + (3/2 - 28/23) . 7/3`
`-> P = 7/3 . [( (-1)/2 + 5/23) + (3/2 - 28/23)]`
`-> P = 7/3 . [(-1)/2 + 5/23 + 3/2 - 28/23]`
`->P = 7/3 . [( (-1)/2 + 3/2) + (5/23 - 28/23)]`
`-> P = 7/3 . [1 + (-1)]`
`-> P = 7/3 . 0`
`-> P=0`
Vậy ...
`Q = (0,75 - 0,6 + 3/7 + 3/13)/(2,75 - 2,2 + 11/7 + 11/13)`
`-> Q= (3/4 -3/5 + 3/7 + 3/13)/(11/4 - 11/5 + 1/7 + 11/13)`
`-> Q = (3 (1/4 - 1/5 + 1/7 + 1/13) )/(11 (1/4 - 1/5 + 1/7 + 1/13) )`
`-> Q = 3/11`
Vậy ...