. x= and 2x2+x=5 Answer to the hundredths. List smaller solution first. x= and show how to find the zeros

1 answer

To solve the equation \(2x^2 + x - 5 = 0\) and find the zeros, we will use the quadratic formula, which is given by:

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

In our equation, we have:

  • \(a = 2\)
  • \(b = 1\)
  • \(c = -5\)

Now, we will substitute these values into the quadratic formula:

  1. Calculate the discriminant (\(b^2 - 4ac\)): \[ b^2 - 4ac = 1^2 - 4(2)(-5) = 1 + 40 = 41 \]

  2. Find the two solutions using the quadratic formula: \[ x = \frac{-1 \pm \sqrt{41}}{2 \cdot 2} = \frac{-1 \pm \sqrt{41}}{4} \]

  3. Calculate the two possible values for \(x\):

    • For the positive root: \[ x_1 = \frac{-1 + \sqrt{41}}{4} \]
    • For the negative root: \[ x_2 = \frac{-1 - \sqrt{41}}{4} \]
  4. Next, we can approximate these values. First, we find \(\sqrt{41}\): \[ \sqrt{41} \approx 6.403 \]

  5. Calculate \(x_1\) and \(x_2\):

    • For \(x_1\): \[ x_1 = \frac{-1 + 6.403}{4} \approx \frac{5.403}{4} \approx 1.35075 \]
    • For \(x_2\): \[ x_2 = \frac{-1 - 6.403}{4} \approx \frac{-7.403}{4} \approx -1.85075 \]
  6. Rounding to the hundredths place, we get:

    • \(x_1 \approx 1.35\)
    • \(x_2 \approx -1.85\)

Thus, the solutions, listed in increasing order, are: \[ x = -1.85, \quad 1.35 \]