How do you solve $x^2-x-1=0$ using the quadratic formula?

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Answer 1 · 2017-07-24T07:22:41

See below

$x=1.62 or x= -0.62$

The quadratic formula is $[-b+-sqrt(b^2-4ac)]/(2a)$

this is used for formulas $ax^2+bx+c=0$

in your problem, $" "x^2−x−1=0" "$ a=1, b=-1, c=-1#

substitute into quadratic $" "[-(-1)+-sqrt((-1)^2-4(1)(-1))]/(2*1)$

this equals $" "(1+-sqrt(1+4))/2$

$(1+sqrt5)/2 or (1-sqrt5)/2$

$x=1.62 or x= -0.62$

How do you solve x^2-x-1=0x^2-x-1=0 using the quadratic formula?