Ответ тут ........ .........
1)(а+9)2+2а(а+9)=а2+18а+81+2а2+18а=3а2+36а
log25(9) - log5(3) = 1/2*2*log5(3) - log5(3) = 0
Cos 146= - cos(180-34)
-4cos34/cos34=-4
<span>1)a^2+ab+x=a</span>²+ab+1/4 b²=<span>(а+1/2 b)</span>²<span>
2)x+6a+9a^2=1+6a+9a</span>²=(1+3a)²