Question

if x^3-y^3=9 and x-y=3 then the value of x^4+y^4 is ​

Answer 1

Step-by-step explanation:

x³-y³=9

or (x-y)³+3 x y (x-y)=9

or 3³+3xy (3) =9. (given x-y=3)

or 9xy = 9-27

or xy = -18/9

or xy =-2

x⁴+y⁴

= (x²)² +(y²)²

= (x²+y²)²-2x²y²

= { (x-y)²+2xy}²-2(-2)² [xy=-2]

= { 3²+2(-2)}²-2×4

= (9-4)²-8

= 5²-8

= 25-8

= 17(ans)