What value of $k$ will make $4x^2 - 20x + k$ the square of a binomial?

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

sine

step-by-step explanation:

not only in mathematics, scientific proof also are required in the other field of science. also maths proofs are of particular structure, containing steps and logics. so proving is like doing science, it is science. that's why it is important to prove. 

an inaccurate proof leads to errors, or stating results that are not accurate.  which wil mess the probelm up you dont want this