<span>(7p+2q)^2+(7p-2q)^2=</span>
<span>=49*q^2+28*p*q+49*p^2+4*q^2-28*p*q+49*p^2=</span>
<span>8*q^2+98*p^2</span>
<span> </span>
<span>(3d+5c)^2-(3d-5c)^2=</span>
<span>=9*d^2+30*c*d+25*c^2-9*d^2+30*c*d-25*c^2=</span>
=60*c*d
250t/3 +6t/3=256t/6=256•(-4t/6) = 1024t/6
(х-у)(х+у)=16;
х(х-у)=10;
1+у/х=1,6;
у=0,6х;
0,4х²=10;
у=±3;
х=±5.
<span>Ответ: (-3;-5), (3;5).</span>