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### Section 2.5 : Quadratic Equations - Part I

6. Solve the following quadratic equation by factoring.

${z^2} - 16z + 61 = 2z - 20$

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Start Solution

The first thing we need to do is get everything on one side of the equation and then factor the quadratic.

\begin{align*}{z^2} - 18z + 81 & = 0\\ {\left( {z - 9} \right)^2} & = 0\end{align*} Show Step 2

From the factored form we can quickly see that the solution is : $\require{bbox} \bbox[2pt,border:1px solid black]{{z = 9}}$