<span>1) 3a(a+2)-(a+3)²= 3a(a+2)-(a+3)(a+3)=3a²+6a-(a²+6a+9)=2a²-9</span>
<span><span>2) 3(y-1)²+6y = 3(y-1)(y-1)+6y=3(y²-2y+1)+6y=3y²-6y+3+6y=3y²+3=3(y²+1)</span></span>
<span><span><span>3) 8c+4(1-c)² = 8c+4(1-2c+c²)=8c+4-8c+4c²=4(c²+1)</span></span></span>
<span><span><span><span>4) 4ab+2(a-b)</span>² = 4ab+2(a²-2ab+b²)=4ab+2a²-4ab+2b²=2(a²+b²)</span></span></span>
<span><span><span><span>5) 3(x+y)²-6xy = 3(x²+2xy+y²)-6xy=3x²+6xy+3y²-6xy=3(x²+y²)</span></span></span></span>
4х^2+4x+1=0
a=4,b=4,c=1
D=b^2-4ac
D=16-4*4*1=16-16=0(D=0,2 корня)
x=-b+-корень D\2a
x=-4+0\2*4=-4\8=-0.5
Ответ:х=0,5
-6х-2у=9; вместо Х, подставляем -0.5y;
(1-b)(1+b)(1+b^2)^2
(1-(-2))(1+(-2))(1+(-2)^2)^2
(1+2)(1-2)(1+4)^2
3*(-1)*(5)^2=-3*25= -75