If $a^3 + b^3 = 62$ and $ a + b = 2$, then the value of ab is:
Answer & explanation
Correct answer: option 1
a + b = 2
a3 + b3 = 62
(a + b)3 = a3 + b3 + 3ab(a + b)
Cubing the given equation on both the sides,
(a + b)3 = 23
= a3 + b3 + 3ab(a + b) = 8
= 62 + 3ab (2) = 8
= 6ab = 8 – 62
= 6ab = -54
ab = -9