Question icon
Grade 9Algebra

if a4+1\a4=727,then the value of a3-1\a3 is. How to solve it by using formulae

Profile image of amog rao
9 Years agoGrade 9
Answers icon

1 Answer

Profile image of Vikas TU
9 Years ago
a4+1\a4=727
this the given eqn.
Now add 2 both seds so that we can use the suitable identity.
a^4 + 1/a^4 + 2 = 729
(a^2)^2 + 1/(a^2)^2 + 2a^2/a^2 = 27^2
(a^2 + 1/a^2)^2 = 27^2
(a^2 + 1/a^2) = 27
like this now sutract 2 both sides .
R.H.D would become sq. of 5 that is 25.
And u would get,
a – 1/a = 5
now then take cube both sides
and now substitute also (x – 1/x).