If x + y = 36, then find (x - 27)3 + (y - 9)3.

If x + y = 36

|Find = (x - 27)³ + (y - 9)³

If we have the variables more than the equations then we can put the extra variables according to our choice. 

Here we have two variables and one equation so put y = 0 

 x + y = 36 

x + 0 = 36

x = 36

Put in find we get =  (36 - 27)³ + (0 - 9)³ = 9³ - 9³ = 0