20%+(1-20%)(320-x)=320×40%

2个回答

  • 20%+(1-20%)(320-x)=320×40%

    0.2+0.8(320-x)=128

    0.2+256-0.8x=128

    0.8x=0.2+256-128=128.2

    x=128.2÷0.8

    x=160.25

    2(x-2)-3(4x-1)=9(1-x)

    2x-4-12x+3=9-9x

    12x-2x-9x=-4+3-6

    x=-7

    (x-1)-(3x+2)=-(x-1)

    x-1-3x-2=-x+2

    3x-x-x=-1-2-2

    x=-5

    1/2(1/2x-1)-1=1

    1/2(1/2x-1)=2

    1/2x-1=4

    1/2x=5

    x=10

    1-3(8-x)=-2(15-2x)

    1-24+3x=-30+4x

    4x-3x=-1-24+30

    x=7

    1/5x-1/2(3-2x)=1

    1/5x-3/2+x=1

    6/5x=1+3/2=5/2

    x=5/2÷6/5

    x=25/12

    -x=2/5x+1

    x+2/5x=-1

    7/5x=-1

    x=-1÷7/5

    x=-5/7