解方程:
8X=24??????2.4+8a=16???????5.5X÷6=11???????3.6X+2.4X=10.8.
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解:(1)8X=24,
????? 8X÷8=24÷8,
????????? X=3;
(2)2.4+8a=16,
?2.4+8a-2.4=16-2.4,
???????? 8a=13.6,
????? 8a÷8=13.6÷8,
??????????a=1.7;
(3)5.5X÷6=11,
? 5.5X÷6×6=11×6,
??????? 5.5X=66,
?? 5.5X÷5.5=66÷5.5,
???????????X=12;
(4)3.6X+2.4X=10.8,
? (3.6+2.4)X=10.8,
??????????? 6X=10.8,
???????? 6X÷6=10.8÷6,
???????????? X=18.
解析分析:(1)根据等式的性质,两边同除以8即可;(2)根据等式的性质,两边同减去2.4,再同除以8即可;(3)根据等式的性质,两边同乘6,再同除以5.5即可;(4)先运用乘法分配律的逆运算,原式变为(3.6+2.4)X=10.8,即6X=10.8,根据等式的性质,两边同除以6即可.
点评:此题考查了根据等式的性质解方程,即等式两边同加、同减、同乘或同除以一个数(0除外),等式的左右两边仍相等;注意“=”号上下要对齐.