A^2+5a+6=0 D=25-24=1 a1=(-5+1)/2=-2 a2=(-5-1)/2=-3
a^2+5a+6=(a+3)(a+2)
(a+3)(a+2) (a+3)(a+2) a+2
--------------- = --------------- = --------
a^2-9 (a-3)(a+3) a-3
Отв под номером 4, снач корень 31, 5.5,
A)
(b-a)/a²b + (3a+b)/ab² - (3a²-4b²)/a²b² =
= [b(b-a) + a(3a+b) - 3a² - 4b²] / a²b² =
= (b²-ab+3a²+ab-3a²-4b²) / a²b² =
=-3b²/a²b² = -3/a²
б)
x/(2(x-1)) - 3/(2x+2) +(x-2)/(x²-1) =
= [x(x+1) - 3(x-1) + 2(x-2)] / 2(x-1)(x+1) =
= (x²+x-3x+3+2x-4) / 2(x-1)(x+1) =
= (x²-1) / 2(x-1)(x+1) =
=(x-1)(x+1) / 2(x-1)(x+1) =1/2
(3cos(π-x)+sin(π/2+x))/cos(3π+x)=(-3cosx+cosx)/(-cosx)=2cosx/cosx=2
1. -1/2-5*(-1/8)=-1/2+5/8=1/8
2. а)243>125
б) (-1/243)<1/3125
в) 1. 003003001 > 0,7873532249
г) 59 049 > 1024