Question

if x+y=10 and xy=21 , find x^3+y^3

Answer 1

ANSWER:

You have the system of two equations 

. 

Express  y  from the first equation   y = 10-x   and substitute it into the second equation.  You will have 

x*(10-x) = 21, 

 = . 


Apply the quadratic formula to solve this quadratic equation. You will get 

 = 3,    = 7. 

It means that the original system has the solutions 

x = 3,  y = 7       and 
x = 7,  y = 3. 

Based on it,  calculate  X^3+Y^3
 
HOPE IT HELPED YOU 
PLZ MARK IT AS BRAINLEST