For any non-zero natural numbers x and y, the symbol "√" is defined to represent an operation, and X √ y = {[x * x-x * (x-1)] + y * y * y-5.2} * 2-1 So 5 √ 5 =?

For any non-zero natural numbers x and y, the symbol "√" is defined to represent an operation, and X √ y = {[x * x-x * (x-1)] + y * y * y-5.2} * 2-1 So 5 √ 5 =?

{[x*x-x*(x-1)]+y*y*y-5.2}*2-1
={[5*5-5*(5-1)]+5*5*5-5.2}*2-1
=(5+125-5.2)*2-1
=259.8-1
=258.8