a. 7- | 63 - x | = 1535 - 287 - 1435 + ( -13 )
7 - | 63 - x | = ( 1535 - 1435 ) - ( 287 + 13 )
7 - | 63 - x | = 100 - ( 300 )
7 - | 63 - x | = -200
| 63 - x | = 207
`=>` \(\left[ \begin{array}{l}63-x=207\\63-x=-207\end{array} \right.\)
`=>` \(\left[ \begin{array}{l}x=-144\\x=270\end{array} \right.\)
Vậy . . .
a. ( 19x + 88 ) : 7 = `(13-8)^2` - `8^2`
( 19x + 88 ) : 7 = `5^2` - `8^2`
( 19x + 88 ) : 7 = 25 - 64
( 19x + 88 ) : 7 = -39
19x + 88 = -273
19x = -361
x = -19
Vậy x = -19