If x2 + y2 = 45 and x - y = 5 then what is the value of x3 - y3?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 275
Given that
x2 + y2 = 45 & x - y = 5
(x - y )2 + 2xy = 45
25 + 2xy = 45
2xy = 45 - 25
xy = 20/2 = 10
x3 - y3 = (x -y) (x2 + y2 + xy) = 5 * (45 + 10)
= 5 * 55 = 275