What are the solutions of the equation x4-9x2+8=0?
use u substitution to solve.

answer

explanation

the given equation is

we can rewrite this as:

let

then the equation becomes:

the factors of 8 that sum up to -9 are {-1,-8}

we split the middle term with these factors to obtain,

we factor by grouping to obtain:

apply the zero product property to get:

but

presidency should be the title

i think it was   tsar alexander ii