- #1
johnnyies
- 93
- 0
Homework Statement
Find all numbers x for which
x2+x+1 > 2 or x2+x-1>0
Homework Equations
none
The Attempt at a Solution
essentially what I did is used the quadratic formula and I got x= [tex]\frac{-1\pm\sqrt{5}}{2}[/tex]
then I graphed the function and found that x2+x-1 > 0 when x < [tex]\frac{-1-\sqrt{5}}{2}[/tex] or when x > [tex]\frac{-1+\sqrt{5}}{2}[/tex]
I'm asking if there is a non-graphical method to solving this. It's a simple algebra question I don't remember how to solve.
This is from Spivak's calculus 3ed, ch 1 problem 4 vi.