Решите уравнения: 1) 9y + 9 – y3 – y2 = 0 2) (3b – 2)2 – (b + 1) 2 = 0

Question

Решите уравнения: 1) 9y + 9 – y3 – y2 = 0 2) (3b – 2)2 – (b + 1) 2 = 0

Answer 1

9(y+1)-y²(y+1)=0

(y+1)(9-y²)=0

(y+1)(3-y)(3+y)=0

y1= -1, y2= -3,  y3= 3

9b²-12b+4-b²-2b-1=0

8b²-14b+3=0

D= 196-96=100

b1= (14-10)/16= 1/4

b2= (14+10)/16= 24/16= 3/2