a^2-4a-1=0 a is not = 0 find a+1/a
Answers
Answered by
11
Step-by-step explanation:
a² - 1 = 4a
a - 1/a = 4
Doing square both side
a² + 1/a² - 2 = 16
a² + 1/a² = 18
a² + 1/a² + 2 = 20
(a + 1/a)² = 20
a + 1/a = √20
a + 1/a = 2√5
Similar questions