1)(3x-4y)²= 9x²-24xy+16y<span>²
2)</span>(8b+5a)(8b-5a)=64b²-25a²
X²+2·5/2·x+(5/2)²=x²+5x+25/4=(x+5/2)²;
x²-2·7·x+7²=x²-14x+49=(x-7)²
(а-3b)^2+(3a+b)^2= 1<span>а</span>²<span>- 6ав +9в</span>²<span>+9a</span>²<span>+6ав +1в</span>² = 10а² +10в²=10(а²+в²)