3x² – x – 1 = 0
x = -1 – √11/6 or x = -1 + √11/6
x = 1 – √11/6 or x = 1 + √11/6
x = -1 – √13/6 or x = -1 + √13/6
x = 1 – √13/6 or x = 1 + √13/6
Question & Answer
What are the possible values of x for the equation 3x² – x – 1 = 0?
1 Answer
Verified archiveTo solve the equation ( 3x² – x – 1 = 0 ), we can use the quadratic formula:
[
x = frac{-b pm sqrt{b^2 – 4ac}}{2a}
]
In this case, ( a = 3 ), ( b = -1 ), and ( c = -1 ).
First, we calculate the discriminant ( b^2 – 4ac ):
[
(-1)^2 – 4(3)(-1) = 1 + 12 = 13
]
Now, we can apply the quadratic formula:
[
x = frac{-(-1) pm sqrt{13}}{2(3)} = frac{1 pm sqrt{13}}{6}
]
This gives us the solutions:
[
x = frac{1 – sqrt{13}}{6} quad text{or} quad x = frac{1 + sqrt{13}}{6}
]
Looking at the options provided, the correct answers are:
– ( x = 1 – frac{sqrt{13}}{6} )
– ( x = 1 + frac{sqrt{13}}{6} )
So, the correct answer is:
x = 1 – √13/6 or x = 1 + √13/6.