Answer:
k = 25
Step-by-step explanation:
(2x - sqrt(k) )^2 Expand this as a binomial
4x^2 - 4x*sqrt(k) + k The middle term must be -20x Solve for k so it is
-4xsqrt(k) = - 20x Divide by -4x
sqrt(k) = -20x/-4x Do the division
sqrt(k) = 5 Square both sides
k = 25
