a: ((m-2n)*(m-2n)):((m-2n)*(m+2n)=(m-2n):(m+2n)
<span> 21 <span>></span> 18,75; 8,006<span><</span> 9,0001; 7,2 <span><</span> 7,2005; 4,009 <span>></span> 3,999.</span>