1) <span>(0,8х+3,2):0,4-7,2=1,8
</span><span>(0,8х+3,2):0,4=1,8+7,2</span>
<span>(0,8х+3,2):0,4=9</span>
<span>0,8х+3,2=9*0,4</span>
<span>0,8х+3,2=3,6</span>
<span>0,8х=3,6-3,2</span>
<span>0,8х=0,4</span>
<span>х=0,4:0,8</span>
<span>х=0,5</span>
<span>Ответ: 0,5.</span>
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<span>2) <span>9,99-0,99:(99у-9,9)=9,09 </span></span>
<span><span><span>0,99:(99у-9,9)=9,99-9,09 </span></span></span>
<span><span><span>0,99:(99у-9,9)=0,9</span></span></span>
<span><span><span>99у-9,9=0,99:0,9</span></span></span>
<span><span><span>99у-9,9=1,1</span></span></span>
<span><span><span>99у=1,1+9,9</span></span></span>
<span><span><span>99у=11</span></span></span>
<span><span><span>у=11:99</span></span></span>
<span><span><span>у=1/9</span></span></span>
<span><span><span>Ответ: 1/9.</span></span></span>
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<span><span><span>3) <span>(0,2х-22):2,2+2=20,2</span></span></span></span>
<span><span><span>(0,2х-22):2,2=20,2-2</span></span></span>
<span><span><span>(0,2х-22):2,2=18,2</span></span></span>
<span><span><span>0,2х-22=18,2*2,2</span></span></span>
<span><span><span>0,2х-22=40,04</span></span></span>
<span><span><span>0,2х=40,4+22</span></span></span>
<span><span><span>0,2х=62,04</span></span></span>
<span><span><span>х=62,04:0,2</span></span></span>
<span><span><span>х=310,2</span></span></span>
<span><span><span>Ответ: 310,2.
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