Question

ifx-y=7andx^3-y^=133,find xy​

Answer 1

Answer: xy = -10 ,

to verify you can also check that x =5 and y = -2    

Step-by-step explanation:

(x-y)^2= 7^2

x^2 -2xy +y^2 = 49

x^2 +y^2 = 49 +2xy   .......(1)

X^3 -y^3 = 133

(x-y)(x^2 +y^2 +xy) = 133

(7)(49+2xy+xy) = 133   (∵ x - y = 7 and from eq (1), x^2 +y^2 = 49 + 2xy)

49 +2xy +xy = 133/7

49 + 3xy = 19

3xy = -30

xy = -10