find the value of c such that each expression is a perfect square trinomial

2. The given expression is;
[tex]z^2+2z+c[/tex]We want to make the expression a perfect square trinomial.
In other words, we want to "complete the square".
In order to complete the square, we need to make c to be equal to
the square of the coefficient of the first power term divided by twice the coefficient of the first power term.
In other words,
[tex]c=(\frac{b}{2a})^2[/tex]Here, b =2 and a =1, so;
[tex]c=(\frac{2}{2\times1})^2=1[/tex]Therefore, the value of c to be added to make the expression a perfect square is 1
4. We have to find c;
[tex]p^2-11p+c[/tex]We know that; a = 1 and b = -11 , so ;
[tex]\begin{gathered} c=(\frac{b}{2a})^2=(\frac{-11}{2})^2 \\ c=30.25 \end{gathered}[/tex]Therefore, the value of c to be added to make the expression a perfect square is 30.25