Which of the following is a solution to the quadratic equation 2x2−9x=4

? Assume that the solution has been rounded to the nearest hundredth. if applicable.(1 point)
Responses

x=4.77
x equals 4.77

x=−0.91
x equals negative 0.91

x=−0.77
x equals negative 0.77

x=4.91

1 answer

To solve the quadratic equation \(2x^2 - 9x = 4\), we first rearrange it into standard form:

\[ 2x^2 - 9x - 4 = 0 \]

Next, we can use the quadratic formula \(x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\), where \(a = 2\), \(b = -9\), and \(c = -4\).

Calculating the discriminant:

\[ b^2 - 4ac = (-9)^2 - 4(2)(-4) = 81 + 32 = 113 \]

Now substituting back into the quadratic formula:

\[ x = \frac{-(-9) \pm \sqrt{113}}{2 \cdot 2} \] \[ x = \frac{9 \pm \sqrt{113}}{4} \]

Next, we calculate \(\sqrt{113}\) (approximately 10.63014581273465):

So we have two potential solutions:

\[ x = \frac{9 + 10.63014581273465}{4} \approx \frac{19.63014581273465}{4} \approx 4.9075 \]

and

\[ x = \frac{9 - 10.63014581273465}{4} \approx \frac{-1.63014581273465}{4} \approx -0.4075 \]

Rounding these to the nearest hundredth gives:

  1. \(x \approx 4.91\)
  2. \(x \approx -0.41\)

Now let's match these results against the provided responses. Rounding "4.91" matches one of the options.

Thus, the correct answer is:

x = 4.91