1)<span> .х²-1=0</span>
<span>х²=1</span>
<span>х=+-1</span>
<span><span>2) х²-9=0</span></span>
<span><span> х²=9</span></span>
<span><span>х=+-3</span></span>
<span><span>3)<span>х²-25=0</span></span></span>
<span><span><span>х²=25</span></span></span>
<span><span><span>х=+-5</span></span></span>
<span><span><span>4)<span>3-12х²=0</span></span></span></span>
<span><span><span><span>-12х²=-3</span></span></span></span>
<span><span><span><span>х²=4</span></span></span></span>
<span><span><span><span>х=+-2</span></span></span></span>
<span><span><span><span>5)<span> <span> 7=28х²</span></span></span></span></span></span>
1=4х²
х²=+-1/4