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

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  • 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.