<span> x+x+x=30</span>
<span>3х=30</span>
<span>х=10</span>
<span>
</span>
<span><span>x*43=43:x</span></span>
<span><span>43*х*х=43 /43</span></span>
<span><span>х^2=1</span></span>
<span><span>x= 1</span></span>
<span><span>x= -1</span></span>
<span>
</span>
<span><span> x-18=16-16</span></span>
<span><span>х-18=0</span></span>
х=0+18
х=18
<span>x+20=12+8</span>
<span>х+20=20</span>
<span>х=20-20</span>
<span>х=0</span>