(2012•宝应县模拟) 求未知数x.

1个回答

  • (1)[1/4]:12=X:[2/5],

    12x=[1/4]×[2/5],

    12x÷12=[1/10]÷12,

    x=[1/120];

    (2)[1.25/0.25]=[x/1.6],

    0.25x=1.25×1.6,

    0.25x÷0.25=2÷0.25,

    x=8;

    (3)1+25%X=3.25,

    1+25%X-1=3.25-1,

    25%x÷25%=2.25÷25%,

    x=9;

    (4)10-15%X=8.5,

    10-15%X+15%x=8.5+15%x,

    10-8.5=8.5+15%x-8.5,

    1.5÷15%=15%x÷15%,

    x=10.