3-(17-x)=289-(36+289)
<=> 3-17+x=289-36-289
<=> -14+x=-36 => x=-22
25-(x+5)=-45-(15-45)
<=> 25-x-5=-45-15+45
<=> 20-x=-15=> x=35
34-(21-x)=(3747-30)-3747
<=> 334-21+x=3747-30-3747
<=> 313+x=-30=> x=-343
3 - ( 17 - x ) = 289 - ( 36 + 289 )
3 - 17 + x = 289 - 36 - 289
- 14 + x = - 36
x = ( - 36 ) - ( - 14 )
x= - 22
25 - ( x + 5 ) = - 45 - ( 15 - 45)
25 - x - 5 = - 45 - 15 + 45
20 - x = - 15
x = 20 - ( - 15 )
x = 35
34 - ( 21 - x ) = ( 3747 - 30 ) - 3747
34 - 21 + x = 3747 - 30 - 3747
13 + x = - 30
x = ( - 30 ) - 13
x = - 46
Xin lỗi bn mk nhầm
34-(21-x)=(3747-30)-3747
<=> 34-21+x=3747-30-3747
<=> 13+x=-30
<=> x=-43