Question

a3 -b3=(a+b) (a2- + )​

Answer 1

Step-by-step explanation:

a³ + b³ = (a + b)(a² – ab + b²)

you know that

(a + b)³ = a³ + 3ab(a + b) + b³

then a³ + b³ = (a + b)³ – 3ab(a + b)

= (a + b)[(a + b)² – 3ab]

= (a + b)(a² + 2ab + b² – 3ab)

= (a + b)(a² – ab + b² )

Proof of

a³ – b³ = (a – b)(a² + ab + b²)

you know that

(a – b)³ = a³ + 3ab(a – b) – b³

then a³ – b³ = (a – b)³ + 3ab(a – b)

= (a – b)[(a – b)² + 3ab]

= (a – b)(a² – 2ab + b² + 3ab)

= (a – b)(a² + ab + b² )

Answer 2

Answer:

(a+b)(a2-ab+b2)

Step-by-step explanation:

if u multiply

a(a2-ab+b2)+b(a2-ab+b2)

a3-a2b+ab2+a2b-ab2+b3

on cancellation of plus and minus symbols

we get

a3-b3