Giải thích các bước giải:
`1)`
`- ( -3 + 7 - 13 ) + ( -5 + 4 - 8 )`
`=3-7+13-5+4-8`
`=3+4-7-8+13-5`
`=(3+4)-(7+8)+13-5`
`=7-15+13-5`
`=-8+13-5`
`=5-5`
`=0`
`2)`
`c, 12- ( 3 - 2x )= ( 3x + 1 ) - 4`
`=>12-3+2x=3x+1-4`
`=>2x-3x=1-4-12+3`
`=>x.(2-3)=-12`
`=>x.(-1)=-12`
`=>x=12`
`d, 4x - 3= 2x+5 - ( 1 - x) `
`=>4x-3=2x+5-1+x`
`=>4x-2x-x=5-1+3`
`=>x.(4-2-1)=7`
`=>x.1=7`
`=>x=7`
`e, 13- 2x +1 = 30-( 3x -13)`
`=>13-2x+1=30-3x+13`
`=>-2x+3x=30+13-13-1`
`=>x.(-2+3)=29`
`=>x.1=29`
`=>x=29`
`f, 3x + x +5 = 5+ 3x +10`
`=>3x+x-3x=5+10-5`
`=>x.(3+1-3)=10`
`=>x.1=10`
`=>x=10`