D=100-4×25×(-12)=100+1200=1300
<span>12tg(15п/14) / tg(п/14) =12</span><span>tg(pi +pi/14) / tg(п/14) </span>= 12
X²-31=0
x²=31
x(1)=-√31
x(2)=√31
1) (с³-5cd-3d)+(c³+5d+8cd)= c³-5cd-3d+c³+5d+8cd= 2c³+2d+3cd
2) (-5y-4x⁴-2x²y)+(-5x²y-6y-5x⁴)= -5y-4x⁴-2x²y-5x²y-6y-5x⁴=-11y-9x⁴-7x²y
3) (-2m²+3n+6mn²)-(2mn²+3n+m²)= -2m²+3n+6mn²-2mn²-3n-m²=-3m²+4mn²