Which of the following is a solution to the quadratic equation 2x^2 − 5x = 6? Assume that the solution has been rounded to the nearest hundredth, if applicable.

A) x = -1.03
B) x = 0.89
C) x = -0.89
D) x = 1.03

1 answer

To solve the quadratic equation \(2x^2 - 5x = 6\), we first rearrange it into standard form:

\[ 2x^2 - 5x - 6 = 0 \]

Next, we will apply the quadratic formula:

\[ x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \]

Here, \(a = 2\), \(b = -5\), and \(c = -6\).

Calculating \(b^2 - 4ac\):

\[ b^2 = (-5)^2 = 25 \]

\[ 4ac = 4 \cdot 2 \cdot (-6) = -48 \]

So,

\[ b^2 - 4ac = 25 - (-48) = 25 + 48 = 73 \]

Now substituting into the quadratic formula:

\[ x = \frac{-(-5) \pm \sqrt{73}}{2 \cdot 2} \]

\[ x = \frac{5 \pm \sqrt{73}}{4} \]

Calculating \(\sqrt{73}\):

\(\sqrt{73} \approx 8.544\) (rounded to three decimal places)

Now, substituting this value back into the equation for \(x\):

\[ x = \frac{5 \pm 8.544}{4} \]

Calculating the two possible solutions:

  1. \(x_1 = \frac{5 + 8.544}{4} = \frac{13.544}{4} \approx 3.386\)
  2. \(x_2 = \frac{5 - 8.544}{4} = \frac{-3.544}{4} \approx -0.886\)

Rounding \(x_2\) to the nearest hundredth gives:

\[ x_2 \approx -0.89 \]

Thus, the solution to the quadratic equation is:

C) \(x = -0.89\).