Answer:
(B) -4
Step-by-step explanation:
so, do the multiplications and see :
(a - 1/a)² = a² - 2×a/a + 1/a² = a² - 2 + 1/a²
(a + 1/a)² = a² + 2×a/a + 1/a² = a² + 2 + 1/a²
now we need to subtract the second from the first :
(a² - 2 + 1/a²) - (a² + 2 + 1/a²) =
= a² - 2 + 1/a² - a² - 2 - 1/a² = -4
and that's it !
