Question

if x+y=7andxy=12 find the value of x³+y³ ​

Answer 1

Answer:

as per identity (x + y)³ = x³ + y³ + 3xy (x + y).

Using above identity,

x + y = 7 and xy = 12.

On putting the values,

(7)³ = x³ + y³ + 3*12*(7)

343 = x³ + y³ + 252

x³ + y³ = 343 - 252

x³ + y³ = 91.

so there fore the answer we get is 91