Question

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

Answer 1

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}`