Question

解方程15t^3+6t^2-5t-2=0

我知道答案是t=1/根号3 不知道怎么解，麻烦帮忙写下过程，谢谢

Answer 1

5t^2(3t^2-1)+2(3t^2-1)=0
(3t^2-1)(5t^2+2)=0
因为5t^2+2>0
所以(3t^2-1)=0
t^2=1/3
t=(正负)1/根号3

Answer 2

3(5t+2)t^2=5t+2

Answer 3

15t^3+6t^2-5t-2=0
3t^2(5t+2)-(5t+2)=0
(5t+2)(3t^2-1)=0
t=-2/5 3t^2-1=0 t^2=1/3 t=正负1/根号3

Answer 4

15t^3+6t^2-5t-2=0
5t^2(3t^2-1)+2(3t^2-1)=0
(3t^2-1)(5t^2+2)=0
(3t^2-1)=0
t=正负1/根号3