4)15y^3-27y^2+9y=3y(5y^2-9y+3)
5)6a^5-72a^4-48a^2=6a^2(a^3-12a^2-7)
6)-5mn^2-15m^2n-20m^2n^2=-5mn(n+3m+4mn)
Sin²α-1= sin²α-(sin²α+cos²α)= sin²α-sin²α-cos²α= - cos²α
(sinα+cosα)²+(sinα-cosα)²= sin²α+2sinαcosα+cos²α+sin²α-2sinαcosα+cos²α= 2
Решение смотрите на фото.
3х^2+18х=9
3х(х+6)=0
3х=0
х1=0
х+6=0
х2=-6
<span>a) 5(x+1.4y)-0.8(2x+y)=5х+7у-1,6х-0,8у=3,4х+6,2
</span><span>б)2/3(x-y-z)-(2/3x-y-z)=2/3х-2/3у-2/3z-2/3x+y+z=1/3y+1/3z=1/3(y+z)
</span><span>в)-a+0.5(3a+0.2b)-(a+0.1b)=-a+1.5a+0.1b-a-0.1b=-0.5a
</span><span>г)-10(2/5b+1/2)+3/4(8-b)+5b=4b-5+6-3/4b=3.25b+1</span>