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计算下面各题.0.69×12.5×8;4.5+3.8÷(10.4-2.8);3.6÷[1.8×(3.4-2.9)]0.46×3.8+3.54×3.85x+5=25;2x-0.2×1.2=0.36.

题目详情
计算下面各题.
0.69×12.5×8;           4.5+3.8÷(10.4-2.8);   3.6÷[1.8×(3.4-2.9)]
0.46×3.8+3.54×3.8       5x+5=25;                2x-0.2×1.2=0.36.
▼优质解答
答案和解析
①0.69×12.5×8
=0.69×(12.5×8)
=0.69×100
=69

②4.5+3.8÷(10.4-2.8)
=4.5+3.8÷7.6
=4.5+0.5
=5

③3.6÷[1.8×(3.4-2.9)]
=3.6÷(1.8×0.5)
=3.6÷0.9
=4

④0.46×3.8+3.54×3.8
=(0.46+3.54)×3.8
=4×3.8
=15.2

⑤5x+5=25
5x+5-5=25-5
 5x÷5=20÷5
     x=4

⑥2x-0.2×1.2=0.36
      2x-0.24=0.36
 2x-0.24+0.24=0.36+0.24
        2x÷2=0.6÷2
            x=0.3