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Solve the equation by using the quadratic formula. Write imaginary solutions in the form atbi. Express answers in simplified form using intefractions, orradicals.N^2 +18-10The solution set is

Solve the equation by using the quadratic formula. Write imaginary solutions in the-example-1
User Nils Ziehn
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1 Answer

17 votes
17 votes

\text{The solution set is }5\pm\sqrt[]{7}

Step-by-step explanation:
\begin{gathered} n^2\text{ + 18 = }10n \\ n^2\text{ -10n + 18 = 0} \end{gathered}

Using quadratic formula:


x\text{ = }\frac{-b\pm\sqrt[]{b^2-4ac}}{2a}
\begin{gathered} \text{for ax}^2\text{ + bx + c = 0} \\ \text{comparing with the given equation:} \\ a\text{ = 1, b = -10, c = 18} \end{gathered}
\begin{gathered} x\text{ = }\frac{-(-10)\pm\sqrt[]{(-10)^2-4(1)(18)}}{2(1)} \\ x\text{ = }\frac{10\pm\sqrt[]{100-72}}{2} \\ x\text{ = }\frac{10\pm\sqrt[]{28}}{2} \end{gathered}
\begin{gathered} \sin ce\text{ we can't find the squareroot of a 28 without a remainder, we would leave the answer in radicals} \\ x\text{ = }\frac{10\pm\sqrt[]{4*7}}{2}=\text{ }\frac{10\pm2\sqrt[]{7}}{2} \\ x\text{ = }\frac{2(5)\pm2\sqrt[]{7}}{2}=\text{ }\frac{2(5\pm\sqrt[]{7)}}{2} \\ x\text{ = }5\pm\sqrt[]{7} \end{gathered}
\begin{gathered} x\text{ = 5 +}\sqrt[]{7\text{ }}\text{ or } \\ x\text{ = 5 -}\sqrt[]{7\text{ }} \\ \text{The solution set is }5\pm\sqrt[]{7} \end{gathered}

User Rubiela
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