Answer:
0
Step-by-step explanation:
Using the algebraic expansion
x³ + y³ = (x + y)³ - 3xy(x + y)
Given
x³ + y³ - 12xy + 64
= (x + y)³ - 3xy(x + y) - 12xy + 64
Substitute x + y = - 4 into the expression
= (- 4)³ - 3xy(- 4) - 12xy + 64
= - 64 + 12xy - 12xy + 64
= 0
