2x(x - 9)² - x²(x - 9) = 0
(x - 9)[2x(x - 9) - x²] = 0
(x - 9)(2x² - 18x - x²) = 0
(x - 9)(x² - 18x) = 0
x(x - 9)(x - 18) = 0
или x₁ = 0 или x - 9 = 0 или x - 18 = 0
x₂ = 9 x₃ = 18
Отвеи : 0 ; 9 ; 18
A) b5 = b1*q^4
162 = 2*q^4
81 = q^4
q = 3
б) b7 = b1*q^6
ху2-х+5-5у2=х(у2-1)+5(1-у2)=х(у2-1)-5(у2-1)=(у2-1)(х-5)