<span>1. х+3х+5=17</span>
<span> 4х+5=17</span>
<span> 4х=17-5</span>
<span> 4х=12</span>
<span> х=12:4</span>
<span> х=3</span>
<span>
</span>
<span><span>2. 3,5х + 2,2х=4,56</span></span>
<span><span> 5,7х = 4,56</span></span>
<span><span> х= 4,56:5,7</span></span>
<span><span> х=0,8</span></span>