Question

plz answr the question fast i ha ve my test tomorrow

Answer 1

Given x - y = 7 and x^3 - y^3 = 133.

x^3 - y^3 = 133

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

(7)(x^2 + y^2 + xy - 2xy + 2xy) = 133 ( Add and subtract -2xy)

(7)(x^2 + y^2 - 2xy) + 3xy) = 133

(7)(x - y)^2 + 3xy) = 133

(7)(7)^2 + 3xy) = 133

(7)(49 + 3xy) = 133

343 + 21xy = 133

21xy = 133 - 343

21xy = -210

xy = -10



(ii) 

we know that (x - y)^2 = x^2 + y^2 - 2xy

                       (7)^2 = x^2 + y^2 - 2 * -10

                       49 = x^2 + y^2 + 20

                       x^2 + y^2 = 29.


(or)


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

133 = (7)(x^2 + y^2 + -10)

19 = x^2 + y^2 - 10

x^2 + y^2 = 29.



Hope this helps!

Answer 2

HI,

Please see the attached file!


Thanks