If x + y + z = 10 and xy + yz + zx = 15, then find the value of x³ + y³ + z³ - 3xyz .

550

If x + y + z = 10

xy + yz + zx = 15

then find the value of x³ + y³ + z³ - 3xyz = ?

If the number of equations are less than the number of variables then we can put the extra variables according to our choice = 

So here two equations given and three variables are present so put z = 0

If x + y = 10

xy = 15

then find the value of x³ + y³ = ?

If x + y  = n

then, $x^3 + y^3$ = n³ - 3 × n × xy

then, $x^3 + y^3$ = 10³ - 3 × 10 × 15

$x^3 + y^3$ = 1000 - 450 = 550