ANSWER:
5
STEP-BY-STEP EXPLANATION:
The perfect square trinomial is given as follows:
[tex](a\pm b)^2=a^2\pm2ab+b^2[/tex]
Therefore, in this case would be:
[tex]\begin{gathered} x^2+2kx+25 \\ a=x \\ b=5 \\ (x+5)^2=x^2+2\cdot5x+25 \\ k=5 \end{gathered}[/tex]
Therefore the value of k is 5
