Find the Perfect Square Trinomial z^2-4z

$z^{2} - 4 z$

Step 1

To find the $c$ value $c = {(\frac{b}{2})}^{2}$ , divide the coefficient of $z$ by $2$ and square the result.

Divide $4$ by $2$ .

${(- 1 \cdot 2)}^{2}$

Multiply $- 1$ by $2$ .

${(- 2)}^{2}$

Raise $- 2$ to the power of $2$ .

$4$

Step 2

Add $4$ to get the perfect square trinomial.

$z^{2} - 4 z + 4$