tìm x :
1) x + 6 = 12 - (-8)
2) 5 - ( 9 - x ) = 15
3) -(+8) + (18 - x ) = 10
4) 8 - (-12) + 10 = -( 14 - x )
5) -(+12) + (-x) - (-3) = 5- (-7)
6) 14 - x + (-10) = -(-9) + (+15)
7) 12 - (-17) + (-3) = -5 + x
8) 21 - ( 25 - x + 21 ) = - ( 25 - 7 )
9) 12 + ( 23 - x ) = 23 - ( 5 - 12)
10) x + ( 6785 - 86 ) - 6785 = 20 + (-86 + 14)
1: =>x+6=12+8=20
=>x=14
2: =>9-x=-10
=>x=19
3: =>18-x-8=10
=>10-x=10
hay x=0
4: \(\Leftrightarrow8+12+10=-14+x\)
=>x-14=30
hay x=44
5: \(\Leftrightarrow-12-x+3=5+7=12\)
=>-9-x=12
=>-x=21
hay x=-21