Unproctored Placement Assessment
Question 19

Use the quadratic formula to solve for [tex]x[/tex].

[tex]\[ 7x^2 + 3x - 2 = 0 \][/tex]

(If there is more than one solution, separate them with a comma.)

[tex]\[ x = \][/tex]



Answer :

To solve the quadratic equation \(7x^2 + 3x - 2 = 0\) using the quadratic formula, follow these steps:

1. Identify the coefficients: For the quadratic equation \(ax^2 + bx + c = 0\), the coefficients are:
- \(a = 7\)
- \(b = 3\)
- \(c = -2\)

2. Write down the quadratic formula:
[tex]\[ x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \][/tex]

3. Calculate the discriminant (\(\Delta\)):
[tex]\[ \Delta = b^2 - 4ac \][/tex]
Substituting the known values:
[tex]\[ \Delta = 3^2 - 4 \cdot 7 \cdot (-2) = 9 + 56 = 65 \][/tex]

4. Calculate the two solutions using the quadratic formula:
[tex]\[ x = \frac{-b \pm \sqrt{\Delta}}{2a} \][/tex]

Substituting \(a = 7\), \(b = 3\), and \(\Delta = 65\):

For the first solution (\(x_1\)):
[tex]\[ x_1 = \frac{-3 + \sqrt{65}}{2 \cdot 7} \][/tex]
Simplifying further:
[tex]\[ x_1 = \frac{-3 + \sqrt{65}}{14} \approx 0.3615898391641821 \][/tex]

For the second solution (\(x_2\)):
[tex]\[ x_2 = \frac{-3 - \sqrt{65}}{2 \cdot 7} \][/tex]
Simplifying further:
[tex]\[ x_2 = \frac{-3 - \sqrt{65}}{14} \approx -0.7901612677356107 \][/tex]

5. Write the final solutions:
[tex]\[ x_1 \approx 0.3615898391641821 \][/tex]
[tex]\[ x_2 \approx -0.7901612677356107 \][/tex]

Therefore, the solutions to the quadratic equation \(7x^2 + 3x - 2 = 0\) are:
[tex]\[ x \approx 0.3615898391641821 \quad \text{and} \quad x \approx -0.7901612677356107 \][/tex]