Question

x²-81=025x²=36x³ +64=0（x-1）³ =8

Answer 1

(1)x²-81=0

x²=81,x=±√81=±9

(2)25x²=36

x²=25/36,

x=±√25/36=±5/6

(3)x³ +64=0

x³ =-64,

x=3次√-64=-4

(4)（x-1）³ =8

x-1 =3次√8=2

x=2+1=3