1)<span>(38+b)*12=840</span>
<span>456+12b=840</span>
<span>12b=840-456=384</span>
<span>b=384/12=32</span>
<span>2)<span>14(p-30)=630</span></span>
<span><span>14p-420=630</span></span>
<span><span>14p=630+420=1050</span></span>
<span><span>p=1050/14=75</span></span>
<span><span>3)<span>(43-s)*17=289</span></span></span>
<span><span><span>731-17s=289</span></span></span>
17s=731-289=442
s=442/17=26
<span>
</span>