<span>6,7X+3X+63,5=500</span>
<span>9,7х=436,5</span>
<span>х=45</span>
<span><span> (2,1-0,7X):0,48=3,5</span></span>
<span><span>2,1-0,7X=3,5*0,48</span></span>
<span><span>-0,7х=1,68-2,1</span></span>
<span><span>х=-0,42:(-0,7)</span></span>
<span><span>х=0,6</span></span>