Completing the Square

We want to complete the square for the given expression. To do so, we will first identify $b.$ In a quadratic expression, $b$ is the linear coefficient, which is the number that is multiplied by the $x$-variable. $$\begin{array}{c}{x}^2-5x+c\end{array}$$ Now, we will calculate ${\left(\frac{b}{2}\right)}^2.$ Since we have that $b=\text{-}5,$ we can calculate the value of ${\left(\frac{b}{2}\right)}^2$ by substituting $\text{-}5$ for $b.$ The value of $c,$ which is the number that completes the square, is $c=6.25.$ $$\begin{array}{c}{x}^2-5x+6.25\end{array}$$