2x+1/6-4x-1/8=1 x-1/0.5-x+2/0.3=2 3/4[3/4(12x+1/4)-8]=3/2x+1

1个回答

  • (1)

    2x+1/6-4x-1/8=1

    2x - 4x + 1/24 = 1

    -2x = 23/24

    x = -23/48

    若写成:

    (2x+1)/6-(4x-1)/8=1

    则方程两边都乘以24

    (2x+1)*4 - (4x-1)*3 = 24

    8x + 4 - 12x +3 = 24

    -4x = 17

    x = -17/4

    (2)

    x-1/0.5-x+2/0.3=2

    因为左边x-x消去了未知数,方程无解.

    若写成:

    (x-1)/0.5-(x+2)/0.3=2

    2x-2 - (10/3)x - 20/3 = 2

    (-4/3)x = 32/3

    x = -8

    (3)

    3/4[3/4(12x+1/4)-8]=3/2x+1

    理解为:

    (3/4) * [(3/4) * (12x+1/4) - 8] = (3/2)x + 1

    (3/4) * [9x + 3/16 - 8] = (3/2)x + 1

    (27/4)x + 9/64 - 6 = (3/2)x + 1

    (21/4)x = 7 - 9/64

    x = 439/112