We have the following polynomial:
[tex]4ck^2+10k^2-16ck-40k[/tex]See that 2k is the greatest common factor, then, let's factor it out
[tex]2k(2kc+5k-8c-20)[/tex]We can still do some small factors inside the parenthesis, like:
[tex]\begin{gathered} 2kc+5k-8c-20 \\ \\ k(2c+5)-4(2c+5) \\ \\ (2c+5)(k-4) \end{gathered}[/tex]Then, inside the parenthesis it's
[tex]2k(2c+5)(k-4)[/tex]Therefore, the expression, completely simplified is
[tex]4ck^2+10k^2−16ck−40k=2k(2c+5)(k-4)[/tex]