Question

If x+y+2=0 then x^3+y^3+8equals :​

Answer 1

If a + b + c = 0 then, a³ + b³ + c³ = 3abc

Because a³ + b³ + c³ = 1/2(a + b + c ) (a² + b² + c² - ab - bc - ca)

Now,

When a + b + c = 0 then, a³ + b³ + c³ - 3abc = 0

so, a³ + b³ + c³ = 3abc

Here,

x + y + 2 = 0

so, x³ + y³ + 2³ = 3xy(2)

x³ + y³ + 8 = 6xy

Hope this helps!