求未知数x:4x-3(20-x)=5xx-20.2-X+10.5=3.-数学

题目简介

求未知数x:4x-3(20-x)=5xx-20.2-X+10.5=3.-数学

题目详情

求未知数x:
4x-3(20-x)=5x
x-2
0.2
-
X+1
0.5
=3.
题型:解答题难度:中档来源:不详

答案

①4x-3(20-x)=5x,
          4x-60+3x=5x,
             7x-60=5x,
          7x-60-5x=5x-5x,
             2x-60=0,
          2x-60+60=0+60,
                2x=60,
                 x=30;

class="stub"x-2
0.2
-class="stub"x+1
0.5
=3,
5(x-2)-2(x+1)=3,
       5x-10-2x-2=3,
            3x-12=3,
         3x-12+12=3+12,
                3x=15,
                 x=5.

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