Question

If x-y=4 and xy =21 find x cube - y cube

Answer 1

Answer:

316

Step-by-step explanation:

Given that : x-y =4

xy= 21

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

= (4)^3 +3 (21) (4)

= 64 + 252

= 316.