TBQ - Prove the given statement — task. Maths CBSE Live product, Class 9 (2026-27).

If \(a + b + c = 7\) and \(ab + bc + ca = 14\), then prove that \(a^3 + b^3 + c^3 - 3abc = 49\).

Proof:

Using

i^{i} = a^{2} + b^{2} + c^{2} + 2 (i)

i = a^{2} + b^{2} + c^{2} + i

a^{2} + b^{2} + c^{2} = i

- - - (i)

Now, using the identity

= (i) (i - i)

(using eqns (i) and given)

= i

Did you find an error?

8. TBQ - Prove the given statement