b8:
`a) x+ 3,12=14,6-8,5`
`<=> x+3,12 =6,1`
`<=>x=6,1-3,12`
`<=>x=2,98`
`b) x-5,14=(15,7+2,3).2`
`<=> x-5,14=18.2`
`<=>x-5,14=36`
`<=>x=36+5,14=41,14`
`c)31,5-x=(18,6-12,3):3`
`<=>31,5-x=(6,3):3`
`<=>31,5-x=2,1`
`<=>x=31,5-2,1=29,4`
`d)x.12,5=(32,6 -10,4).5`
`<=>x=((32,6 -10,4).5)/12,5 =8,88`
b9:
`a)2,6(x+3,4)=-13`
`<=>x+3,4=-13/2,6 =-5`
`<=>x=-5-3,4=-8,4`
`b)2,5x -4,16=7,5:1,5`
`<=> 2,5x -4,16=5`
`<=>2,5x=5+4,16=9,16`
`<=>x=9,16/2,5=3,664`
`c)3,4:x -15,6=-16`
`<=>3,4:x =-16+15,6=-1,6`
`<=>x=3,4/(-1,6) =-2,125`