Question

IF x + y + 2 = 0, then write the value of x3 + y3 + 8

Answer 1

We know,
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 [ans]

Answer 2

Answer:

x³ + y³ + 8= 6xy

Step-by-step explanation:

Given x + y + 2 = 0 then

x³ + y³ + 8= (x)³+(y)³+(2)³=0

We know if a+b+c=0 then,

a³+b³+c³=3abc

x³+y³+(2)³=3×x×y×2

x³+y³+8=6xy