Решите уравнение 2) (х-3)(х2+3х+9)-х(х2-16)=21 4) 16х(4х2-5)+17=(4х+1)(16х2-4х+1)

Question

Решите уравнение
2) (х-3)(х2+3х+9)-х(х2-16)=21
4) 16х(4х2-5)+17=(4х+1)(16х2-4х+1)

Answer 1

2) (х-3)(х2+3х+9)-х(х2-16)=21
x³-3³-(x³-16x)=21
x³-27-x³+16x=21
16x=21+27
16x=48
x=48:16
x=3
4) 16х(4х2-5)+17=(4х+1)(16х2-4х+1)
16*4*x³-5*16x+17=(4x)³+1
64x³-80x+17=64x³+1
80x=64x³-64x³+17-1
80x=16
x=16:80
x=1/5=0.2