Abhay's Math

Math home

Did you get x = 2 , n = 4 ?
No ?
Never mind.
Here is the solution. 
					3xn-1 + 5x2 + 20 = 2xn+1

			let xn-1 = a and x2 = b, then xn+1 = xn-1.x2 = ab

			So the equation becomes 3a + 5b + 20 = 2ab

Solve for a and b , then put x2 = b and get integral values of x (reject non - integral solutions) and then again put xn-1 = a getting integral values of n and rejecting others.

So you get the solution as (2,4).

Next