问题
解答题
解方程
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答案
(1)7x-2×9=80,
7x-18=80,
7x-18+18=80+18,
7x=98,
7x÷7=98÷7,
x=14;
(2)13x-7.5x=18.7,
(13-7.5)x=18.7,
5.5x=18.7,
5.5x÷5.5=18.7÷5.5,
x=3.4;
(3)(x+12)×6=108,
(x+12)×6÷6=108÷6,
x+12=18,
x+12-12=18-12,
x=6.