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Solve using the quadratic formula. x2 - x - 1 = 0

Solve using the quadratic formula. x2 - x - 1 = 0-example-1
User Matias Vad
by
7.5k points

1 Answer

5 votes
Answer:
\begin{gathered} x\text{ = }\frac{1\pm\sqrt{5\text{ }}}{2}\text{ \lparen2nd option\rparen} \\ \end{gathered}

Step-by-step explanation:

Given:


x^2\text{ - x - 1 = 0}

To find:

To find x using a quadratic function

The quadratic formula is given as:


$$x\text{ = }\frac{-b\pm\sqrt[]{b^2-4ac}}{2a}$$
\begin{gathered} a\text{ = 1, b = -1, c =-1} \\ \\ \\ x\text{ = }(-(-1)\pm√((-1)^2-4(1)(-1)))/(2(1)) \\ \\ x\text{ = }(1\pm√(1+4))/(2) \end{gathered}
\begin{gathered} x\text{ = }\frac{1\pm\sqrt{5\text{ }}}{2}\text{ \lparen2nd option\rparen} \\ \end{gathered}

User DonP
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