Which component in the Harvest Index calculation

If (x²⁴  +  1)/x¹²  = 7, then the value of (x⁷²  +  1)/x³⁶  is 

If x = (2+√3)/(2-√3), y = (2-√3)/(2+√3)

Then find out the value of (x²+y²-xy)/(x²+y²+xy)

If (a - b - c) = 6, and (ab - bc + ca) = 117, then find the value of (a ²  + b ²  + c ² )

Find the value of the given expression-

(4^x+4 -5× 4^x+2) / 15×4^x – 2²×4^x

[a/(2a²  + 5a + 2)] = 1/6 , then find the value of (a+1)/a ?

A train can cross a pole, a bridge of 720 meter long and platform of 640 meter long in 9 seconds, _____ seconds and 25 seconds, respectively.

For which value of k does the quadratic equation

x² − 4(k + 1)x + (3k² + 8k + 4) = 0

have equal real roots?