-2x+y=11 <=> -2x+y-11=0 l x(-2) <=> 4x-2y+11=0 <=> 7x=-10 <=> x=-1 3|7
2)
4ав^3-a^3в=4ав(в2-а2)=4ав(в-а)(в+а)
-9в-6в^3-в^3=-(9в-6в^3-в^3)=-(3в-в)^2
1
(a²+3)/a³-(3-a)/3a=(3a²+9-3a²+a³)/3a³=(a³+9)/3a³
2
x/(x-1)+x/(x+1)=(x²+x+x²-x)/(x²-1)=2x²/(x²-1)
3
x/(x-2y)-4y²/x(x-2y)=(x²-4y²)/x(x-2y)=(x-2y)(x+2y)/x(x-2y)=(x+2y)/x
4
2a+b -4ab/(2a+b)=(4a²+4ab+b²-4ab)/(2a+b)=(4a²+b²)/(2a+b)
4m³ - 32c³=4(m³ - 8c³)=4(m³ - (2c)³)=4(m-2c)(m²+2mc+4c²)
Cos45° * Sin3105° + 1/2ctg(- 315°) - Cos270° = Cos45° * Sin(360° * 8 + 225°) -
- 1/2ctg(90° *2 + 135°) - Cos270°= Cos45° * Sin225° - 1/2ctg(90°+45°) - Cos270° =
= Cos45° * Sin(180° + 45°) + 1/2tg45° - Cos270° = - Cos45° * Sin45° +
+ 1/2 tg45° - Cos270° = - √2/2 * √2/2 + 1/2 * 1 - 0 = - 1/2 + 1/2 = 0