(1-4y)(9+5y)=9+5y-36y-20y^2=-20y^2-31y+9
D-дискриминант
D=(-31)^2-4*(-20)*9=1681
x1,x2-корни уравнения
x1= -1,8
x2=0,25
An= 4n-17, a(n+1) = 4(n+1) -17=4n+4-17=4n-13
d= a(n+1)-an = 4n-13 - 4n+17 = 4,d=4
<span>15а^3+5b^4.
5(3a^3+b^4)
</span><span>16a^3b^4+4b^4-2a^3b^4.
14a^3b^4+4b^4
2b^4*(7a^3+2)
</span><span>18a^3b^4+5a^3b^4-2a^3b^4.
(18+5-2)a^3b^4
21a^3b^4
</span><span>18a^3b^6+2a^3b^2.
2a^3b^2*(9b^4+1)</span>