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Can you explain and solve for x. `x^2+x-18=0`
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High School Teacher
Solve `x^2+x-18=0` :
The quadratic expression does not factor in the rationals (no rational factors of 18 are 1 unit apart.) So we can use other methods:
(1) If `ax^2+bx+c=0` then the quadratic formula is
`=-1/2+sqrt(73)/2` or `-1/2-sqrt(73)/2`
(2) We can use completing the square:
`x=-1/2+-sqrt(73)/2` as before.
Posted by embizze on June 10, 2013 at 5:45 PM (Answer #1)
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