Question

Ifx - y = 2 and xy = 15 then find the value of x^3 - y^3​

Answer 1

Answer:

Step-by-step explanation:

x²+y²=34

x³-y³=2*(34+15)

=2*49

=98

Answer 2

Answer:

Q) x-y=2 , xy=15 , x^3-y^3= ?

using, a^3-b^3= (a-b)(a^2+ab+b^2)

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

= (2)(x^2+y^2+15) .......(1)

Now, we need to find value of x^2+y^2,

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

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

4 = x^2+y^2 -2(15)

4 = x^2+y^2-30

4+30= x^2+y^2

34 = x^2+y^2

Now, putting value of x^2+y^2 in (1),

x^3-y^3 = (2)(34+15)

= (2)(49)

= 98

Therefore, value of x^3-y^3 is 98.

Here is your solution.....hope it helps!