<span> (138+517)</span>²<span> >138</span>²<span>+517</span>², так как (138+517)²= 138²+517²+2·138·517
(a+b)^2-(a-b)(a+b)=
a²+2ab+b²-(a²-b²)=
a²+2ab+b²-a²+b²=
2ab+2b²=2ab(1+b)
<span>0,3^ (3х-1)<0.09
</span>0,3 ^(3х-1)<0.3^2
3x-1>2
x>1
3x-2/1 x=2/3
3x/4-1/2 x=2/3
<span> -2(1-2x)/x x=1/2</span>