解:(1)6xy﹣3[3y2﹣(x2﹣2xy)+1], =6xy﹣3[3y2﹣x2+2xy+1], =6xy﹣9y2+3x2﹣6xy﹣3, =3x2﹣9y2﹣3; (2)﹣14÷(﹣5)2×(﹣)+|0.8﹣1|, =﹣1÷25×(﹣)+|0.8﹣1|, =+0.2, =; (3)等式左边=x﹣2(x﹣3x+3) =x﹣2x+6x﹣6 =5x﹣6, ∴方程可化为5x﹣6=8, 移项并合并,得5x=14, 系数化为1得x=2.8; (4)去分母,得2(x+1)﹣(x﹣2)=3(4﹣x)+6, 去括号得:2x+2﹣x+2=12﹣3x+6, 移项,得2x﹣x+3x=12+6﹣2﹣2, 合并同类项,得4x=14, 系数化为1,得x=3.5. |