2x - <span> </span><span>песок</span>
<span>5x - </span><span>чернозеm</span>
<span>2x + 5x = 42</span>
<span>7x = 42</span>
<span>x = 6</span>
<span></span>
<span>2 * 6 = 12 - pesok</span>
<span>5 * 6 = 30 - chernozem</span>