If a + b + c = 8,

ab + bc + ca = 20, then

find \(\frac{a^3 + b^3 + c^3 - 2abc}{2}\).

16

No. of equations are two and variables are three, put c = 0

then, a + b = 8

ab = 20

Formula → a³ + b³ = (a + b)³ - 3ab (a + b)

⇒ a³ + b³ = 512 - 3 × 20 (8)

⇒ a³ + b³ = 32

Now, put the value and find,

⇒ \(\frac{a^3 + b^3 + c^3 - 2abc}{2}\) = \(\frac{t\;+\;0\;-\;0}{2}\) = \(\frac{32}{2}\) = 16