А)(y-3)^2-16y^2=y^2-6y+9-16y^2=-15y^2-6y+9=-15y(y+1)+9(y+1)=3(3-5y)(y+1);
б)x^2-y^2-y-x=x^2-y^2-y-x+xy-xy=x(x-y-1)+y(x-y-1)=(x+y)(x-y-1)
<span>8x³-12x²y+6xy²-y³+12xy+3y² = (2х-у)³+3у(4х+у)</span>
X^2 +3x - 10 = 0 D=3^2 - 4*(-10)*1=9+40=49 корень из 49=7 x1=-3+7/2=2 x2=-3-7/2=-5 *-знак умножения /-знак деления
An=a1+d(n-1)
0,5=3,5+6d
-3=6d
D=(-0,5)
{a=0.7b
{a=0.4c
{c-b=42
0.7b=0.4c
b=<u>0.4c</u>
0.7
b=<u>4c </u>
7
c- <u>4c </u>=42
7
7c-4c=42*7
3c=294
c=98
98-b=42
-b=42-98
b=56
a=0.4*987
a=39.2
Ответ: a=39.2
b=56
c=98