Question

Find the value of x^3 + y^3 - 12xy +64 when x+y = (-4)​

Answer 1

Answer:

taking cube both sides we get    (x+y)^3=-4^3=-64

now expanding   x^3+ y^3+3xy(x+y)=-64

putting x+y=-4   we get

x^3+y^3+3xy(-4)=-64

or x^3+y^3-12xy+64=0

Answer 2

Step-by-step explanation:

x^3+y^3 can write as (x+y)^3

so,

(x+y)^3-12xy+64

=(-4)^3-12xy+64

=(-64)-12xy+64

-64 & 64 get cancelled

so the answer is 12xy