问题 解答题

①6x+31=49②7x÷3=8.19③32.8-9x=17.5 ④x-0.36x=16⑤6×7+3x=69⑥6x+2x-56=0.

答案

①6x+31=49,

6x+31-31=49-31,

6x=18,

6x÷6=18÷6,

x=3;

②7x÷3=8.19,

7x÷3×3=8.19×3,

7x=24.57,

7x÷7=24.57÷7,

x=3.51;

③32.8-9x=17.5,

32.8-9x+9x=17.5+9x,

17.5+9x=32.8,

17.5+9x-17.5=32.8-17.5,

9x=15.3,

9x÷9=15.3÷9,

x=1.7;

④x-0.36x=16,

(1-0.36)x=16,

0.64x=16,

0.64x÷0.64=16÷0.64,

x=25;

⑤6×7+3x=69,

42+3x=69,

42+3x-42=69-42,

3x=27,

3x÷3=27÷3,

x=9;

⑥6x+2x-56=0,

(6+2)x-56+56=0+56,

8x=56,

8x÷8=56÷8,

x=7.

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