Question

if
${x}^{2} + {y}^{2} = 4$
and
$x - y = 3$
then find the value of
$x \times x \times x - y \times y \times y$
​

Answer 1

Answer:

Given:

x^2 + y^2 = 4

x - y = 3

Also,

We know that;

=> (x - y)^2 = x^2 + y^2 - 2•xy

=> (3)^2 = 4 - 2•xy

=> 9 = 4 - 2xy

=> 2xy = 4 - 9

=> 2xy = -5

=> xy = -5/2

Now;

We know that;

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

= 3(4 - 5/2)

= 3(8 - 5)/2

= 3•(3)/2

= 9/2

Hence,

The required value of x^3 - y^3 = 9/2.