..............................................................................................................................................
<span>(х-9)</span>²<span>=(х-3)</span>²
<span>х</span>²-18х+81=х²-6х+9
-18х+6х=9-81
<span>-12х=-72
х=6
</span>
X^4-7x^2+6=0
X=-^6
X=-1
X=1
X=^6