Answer:
6
I took the test
a - 1/a =5
take squaring both side
(a - 1/a )^2 = (5)^2
a^2 +1/a^2 -2.a.1/a =25
a^2+1/a^2 -2 =25
a^2+1/a^2 =27 (answer)
that's the solution of the system
