What is the value of k for which (k2 - 5k + 4)x2 + (k2 - 3k - 4)x + (k2 - 4k) = 0 is an identity in x?

If the shares of Raju, Ankit, and Anuj in a total sum of 1 are 0.625, 0.04, and 0.229 respectively, and the remaining share belongs to Ranjan, then the share of Ranjan is:

What is the square root of (7 + 2√10)?

If x2 + 1x2 = 7, then what is the value of x + 1x?