.........................
<span>{x+2y=6
{x-3y=-14
х=6-2у
6-2у-3у=-14
х=6-2у
-5у=-20
х=6-2у
у=4
х=-2
у=4
(-2; 4)</span>
(6b-7)(7+6b)=(42b+36b^2)+(-49-42b)=42b+36b^2-49-42b=36b^2-49
А)16^(1/2)+27^(-1/3)+81^(3/4)-8^(5/3)=4^(2/2)+3^(-3/3)+3^(12/4)-2^(15/3)=4+1/3+3^3-2^5=4+1/3+27-32=1/3-1=-2/3
б) 16^0.4*8^(1/3) 2^1.6*2^(3/3)
------------------- = ------------------ =2^(1.6+1-0.6)=2^2=4
4^0.3 2^0.6