Which of the following is a solution to the quadratic equation 4x2+2x=10? (1 point)

Responses

−2+41√4
the fraction with numerator negative 2 plus square root of 41 and denominator 4

−1−41√4
the fraction with numerator negative 1 minus square root of 41 and denominator 4

−2+92√8
the fraction with numerator negative 2 plus 9 square root of 2 and denominator 8

−1−92√8

1 answer

To solve the quadratic equation \( 4x^2 + 2x = 10 \), we first rearrange the equation into standard form:

\[ 4x^2 + 2x - 10 = 0. \]

Next, we can utilize the quadratic formula \( x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \), where \( a = 4 \), \( b = 2 \), and \( c = -10 \).

First, we calculate the discriminant \( b^2 - 4ac \):

\[ b^2 - 4ac = 2^2 - 4(4)(-10) = 4 + 160 = 164. \]

Now we can plug into the quadratic formula:

\[ x = \frac{-2 \pm \sqrt{164}}{2 \cdot 4} = \frac{-2 \pm \sqrt{164}}{8}. \]

Next, we simplify \( \sqrt{164} \):

\[ \sqrt{164} = \sqrt{4 \cdot 41} = 2\sqrt{41}. \]

Substituting this back into the equation gives:

\[ x = \frac{-2 \pm 2\sqrt{41}}{8} = \frac{-2}{8} \pm \frac{2\sqrt{41}}{8} = \frac{-1 \pm \sqrt{41}}{4}. \]

Thus, the two solutions are:

\[ x = \frac{-1 + \sqrt{41}}{4} \quad \text{and} \quad x = \frac{-1 - \sqrt{41}}{4}. \]

Now we compare these solutions with the provided options:

  1. \(-2 + \frac{4\sqrt{4}}{1}\) (This does not match)
  2. \(-1 - \frac{4\sqrt{41}}{4}\) \(\equiv \frac{-1 - \sqrt{41}}{4}\) (This matches the second solution)
  3. \(-2 + \frac{9\sqrt{2}}{8}\) (This does not match)
  4. \(-1 - \frac{9\sqrt{2}}{8}\) (This does not match)

The correct solution from the options is:

−1−41√4

This corresponds to \( \frac{-1 - \sqrt{41}}{4} \).