Question

Hey Guys, Please Answer this one, Tomorrow is my test.

If x+y+z = 8 and xy+yz+zx= 20 , find the value of x³+y³+z³-3xyz .

Thankyou so much
Please provide answer with complete explanation.

Answer 1

Hello avreen didi



x + y + z = 8 -----( 1 )

xy + yx + zx = 20 ----( 2 )

do the square of equation ( 1 ),

( x + y + z )² = 8²

x² + y² + z² + 2 ( xy + yz + zx ) = 64

x² + y² + z² + 2 × 20 = 64

x² + y² + z² = 64 - 40

x² + y² + z² = 24 ----( 3 )

Now ,..

x³ + y³ + z³ - 3xyz

= ( x + y + z ) [ x² + y² + z² - ( xy + yz + zx ) ]

= 8 × [ 24 - 20]

= 8 × 4

= 32



HOPE IT HELPS YOU!!

Answer 2

Question :


If x+y+z = 8 and xy+yz+zx= 20 , find the value of x³+y³+z³-3xyz .

Solution :

Refer to the above attachment