Question

(x + y)3 - (x - y)3 is equals to

Answer 1

Answer:

We know

a³ + b³ = (a + b)(a² – ab + b²)

so

(x+y)³ + (x-y)³ = ((x+y) + (x-y))((x+y)² – (x+y)(x-y) + (x-y)²)

(x+y)³ + (x-y)³ = (2x)(x²+2xy+y² - x²-y²+x²-2xy+y²)

[use the identities (a+b)²=a²+2ab+b², (a+b)(a-b)= a²-b²]

(x+y)³ + (x-y)³ = (2x)(x²+y²)

Step-by-step explanation:

hope u understood  thanku