Question

x^3+y^3 when x+y=12,xy=27​

Answer 1

Answer:

756

Step-by-step explanation:

(x-y)^2=(x+y)^2-4xy

=144-108

(x-y)^2=36

x-y=6---(1)

x+y=12---(2)

by solving eq (1),(2)

we get

x=9,y=3

x^3 +y^3=9^3+3^3

=756

Answer 2

Answer:

756

Step-by-step explanation:

x+y=12

xy=27

x^3+y^3 =( x+y) (x^2-xy+y^2)

=12 (x^2+y^2-27)

Since we don't know about the value of x^2+y^2,

(x+y)^2= x^2+y^2+2xy

144=x^2+y^2+54

x^2+y^2=90

So,

x^3+y^3= 12(90-27)

= 12(63)

=756