问题 解答题

解方程.

(1)576÷x=2×9

(2)13x+8.6-5x=36.2

(3)6(x-0.3)=1.8

(4)66.6-4x=55÷2

(5)96-3(x-1.3)=15

(6)2x+3x-29=4x.

答案

(1)576÷x=2×9

576÷x×x=2×9×x

576=18x

18x÷18=576÷18

x=32;

(2)13x+8.6-5x=36.2

13x+8.6-5x-8.6=36.2-8.6

8x=27.6

8x÷8=27.6÷8

x=3.45;

(3)6(x-0.3)=1.8

6(x-0.3)÷6=1.8÷6

x-0.3=0.3

x-0.3+0.3=0.3+0.6

x=0.6;

(4)66.6-4x=55÷2

66.6-4x+4x=55÷2+4x

66.6=27.5+4x

4x+27.5=66.6

4x-27.5-27.5=66.6-27.5

4x=39.1

4x÷4=39.1÷4

x=9.775;

(5)96-3(x-1.3)=15

96-3(x-1.3)+3(x-1.3)=15+3(x-1.3)

96=15+3(x-1.3)

15+3(x-1.3)=96

15+3(x-1.3)-15=96-15

3(x-1.3)=81

3(x-1.3)=81

3(x-1.3)=81

3(x-1.3)÷3=81÷3

x-1.3=27

x-1.3+1.3=27+1.3

x=28.3;

(6)2x+3x-29=4x

5x-29=4x

5x-29+29-4x=4x+29-4x

x=29.

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