SOLUTION: please help with this. I dont understand how to use the formula. Use the quadratic formula to solve the equation: 2x^2 - x - 1= 0 Thank you

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Question 43458This question is from textbook college algebra
: please help with this. I dont understand how to use the formula.
Use the quadratic formula to solve the equation:
2x^2 - x - 1= 0

Thank you This question is from textbook college algebra

Answer by prabhjyot(165) About Me  (Show Source):
You can put this solution on YOUR website!
2x%5E2+-+x+-+1=+0
compare the above equation with standard quadratic equation ax%5E2%2Bbx%2Bc=0
we get
a = 2
b = -1
c = -1
Discriminant: b%5E2-4ac = %28-1%29%5E2%2B4%2A2%2A%28-1%29+=+9
Discriminant (9) is greater than zero. The equation has two solutions.
x=%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F2a
x=%28-%28-1%29%2B-sqrt%28%28-1%29%5E1-4%2A2%2A%28-1%29%29%29%2F%282%2A2%29
x1,2 = (1 ± 3) / 2*2
or
x1 = 4 / 4 = 1
x2 = -2 / 4 = -1/2
or
x1,2 = 1, -0.5

Equation factored: 2(x-1)(x+0.5)