解下列方程.x+ 7 8 x=42 (

1个回答

  • (1)x+

    7

    8 x=42

    15

    8 x÷

    15

    8 =42÷

    15

    8

    x=22.4;

    (2)(

    5

    8 +

    5

    6 )x=

    7

    10

    35

    24 x=

    7

    10 ,

    35

    24 x÷

    35

    24 =

    7

    10 ÷

    35

    24 ,

    x=

    12

    25 ;

    (3)

    4

    5 ×5-12x=1

    4-12x=1,

    4-12x+12x=1+12x,

    1+12x=4,

    1+12x-1=4-1,

    12x=3,

    12x÷12=3÷12,

    x=

    1

    4 .