解:(1)4.5×6+4x=41,
27+4x=41,
27+4x-27=41-27,
4x=14,
4x÷4=14÷4,
x=3.5;
(2)7x-3.4x=0.72,
3.6x=0.72,
3.6x÷3.6=0.72÷3.6,
x=0.2;
(3)2x+1.5x=42,
3.5x=42,
3.5x÷3.5=42÷3.5,
x=12;
(4)(x-4.5)×6=31.8,
6x-27=31.8,
6x-27+27=31.8+27,
6x=58.8,
6x÷6=58.8÷6,
x=9.8;
(5)x÷1.2=8,
x÷1.2×1.2=8×1.2,
x=9.6,
(6)(x+1.7)÷3=1.4,
(x+1.7)÷3×3=1.4×3,
x+1.7=4.2,
x+1.7-1.7=4.2-1.7,
x=2.5.
分析:(1)原式變?yōu)?7+4x=41,根據(jù)等式的性質(zhì),兩邊同減去27,再同除以4即可;
(2)原式變?yōu)?.6x=0.72,根據(jù)等式的性質(zhì),兩邊同除以3.6即可;
(3)原式變?yōu)?.5x=42,根據(jù)等式的性質(zhì),兩邊同除以3.5即可;
(4)原式變?yōu)?6x-27=31.8,根據(jù)等式的性質(zhì),兩邊同加上27,得6x=58.8,兩邊同除以6即可;
(5)根據(jù)等式的性質(zhì),兩邊同乘1.2即可;
(6)根據(jù)等式的性質(zhì),兩邊同乘3,得x+1.7=4.2,兩邊再同減去1.7即可.
點評:在解方程時應(yīng)根據(jù)等式的性質(zhì),即等式兩邊同加上、同減去、同乘上或同除以某一個數(shù)(0除外),等式的兩邊仍相等,同時注意“=”上下要對齊.