Question

X+y=6 and xy=8then find x3 + y3

Answer 1

Answer:

x³ + y³ = 62

step-by-step explanation:

Given:

x + y = 6 and xy = 8

To find:

x³ + y³

Solution:

Since, x + y = 6

=> (x + y)³ = 6³ [cubing on both

the sides]

=> x³+ y³+3xy (x + y)= 216 [(a+b)³=a³+b³+3ab(a+b)]

=> x³ + y³ + 3(8)(6)= 216 [given; x+y=6 & xy=8]

=> x³ + y³ + 144= 216

=> x³ + y³ = 216 - 144

=> x³ + y³ = 62

Answer..

Hope this helped you...