Welcome to Westonci.ca, the Q&A platform where your questions are met with detailed answers from experienced experts. Join our platform to connect with experts ready to provide precise answers to your questions in different areas. Explore comprehensive solutions to your questions from a wide range of professionals on our user-friendly platform.

Which shows the correct substitution of the values \(a\), \(b\), and \(c\) from the equation \(0=-3x^2-2x+6\) into the quadratic formula?

Quadratic formula:
[tex]\[x=\frac{-b \pm \sqrt{b^2-4ac}}{2a}\][/tex]

A. \(x=\frac{-(-2) \pm \sqrt{(-2)^2-4(-3)(6)}}{2(-3)}\)

B. \(x=\frac{-2 \pm \sqrt{2^2-4(-3)(6)}}{2(-3)}\)

C. \(x=\frac{-(-2) \pm \sqrt{(-2)^2-4(3)(6)}}{2(3)}\)

D. [tex]\(x=\frac{-2 \pm \sqrt{2^2-4(3)(6)}}{2(3)}\)[/tex]

Sagot :

To determine the correct substitution of the values \(a = -3\), \(b = -2\), and \(c = 6\) into the quadratic formula \(x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\), we need to substitute these values step-by-step. Let's analyze each option to see which one is correctly substituted.

### Quadratic Formula:
The quadratic formula is given by:
[tex]\[ x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \][/tex]

### Substituting Values:
The given equation is:
[tex]\[ 0 = -3x^2 - 2x + 6 \][/tex]

Here, \( a = -3 \), \( b = -2 \), and \( c = 6 \).

To substitute these into the quadratic formula, we follow these steps:

1. Substitute \( b = -2 \):
[tex]\[ x = \frac{-(-2) \pm \sqrt{(-2)^2 - 4ac}}{2a} \][/tex]
[tex]\[ x = \frac{2 \pm \sqrt{4 - 4ac}}{2a} \][/tex]

2. Substitute \( a = -3 \):
[tex]\[ x = \frac{2 \pm \sqrt{4 - 4(-3)c}}{2(-3)} \][/tex]
[tex]\[ x = \frac{2 \pm \sqrt{4 + 12c}}{-6} \][/tex]

3. Substitute \( c = 6 \):
[tex]\[ x = \frac{2 \pm \sqrt{4 + 12 \cdot 6}}{-6} \][/tex]
[tex]\[ x = \frac{2 \pm \sqrt{4 + 72}}{-6} \][/tex]
[tex]\[ x = \frac{2 \pm \sqrt{76}}{-6} \][/tex]

### Evaluating the Given Options:
From the provided options, let's find the one that matches this substitution process:

1. \( x = \frac{-(-2) \pm \sqrt{(-2)^2 - 4(-3)(6)}}{2(-3)} \)

2. \( x = \frac{-2 \pm \sqrt{2^2 - 4(-3)(6)}}{2(-3)} \)

3. \( x = \frac{-(-2) \pm \sqrt{(-2)^2 - 4(3)(6)}}{2(3)} \)

4. \( x = \frac{-2 \pm \sqrt{2^2 - 4(3)(6)}}{2(3)} \)

### Analyzing Each Option:

1. Substituting correctly:
[tex]\[ x = \frac{-(-2) \pm \sqrt{(-2)^2 - 4(-3)(6)}}{2(-3)} \][/tex]
This equals:
[tex]\[ x = \frac{2 \pm \sqrt{4 + 72}}{-6} \][/tex]
[tex]\[ x = \frac{2 \pm \sqrt{76}}{-6} \][/tex]
This option matches our steps.

2. Incorrect because \( -2 \) is used instead of \( -(-2) \):
[tex]\[ x = \frac{-2 \pm \sqrt{2^2 - 4(-3)(6)}}{2(-3)} \][/tex]
[tex]\[ x = \frac{-2 \pm \sqrt{4 + 72}}{-6} \][/tex]
[tex]\[ x = \frac{-2 \pm \sqrt{76}}{-6} \][/tex]

3. Incorrect because \( a = 3 \) instead of \( a = -3 \):
[tex]\[ x = \frac{-(-2) \pm \sqrt{(-2)^2 - 4(3)(6)}}{2(3)} \][/tex]
[tex]\[ x = \frac{2 \pm \sqrt{4 - 72}}{6} \][/tex]
[tex]\[ x \neq \frac{2 \pm \sqrt{76}}{-6} \][/tex]

4. Incorrect because both \( b \) and \( a \) are mis-used:
[tex]\[ x = \frac{-2 \pm \sqrt{2^2 - 4(3)(6)}}{2(3)} \][/tex]
[tex]\[ x = \frac{-2 \pm \sqrt{4 - 72}}{6} \][/tex]

### Conclusion:
The correct substitution of the values \( a = -3 \), \( b = -2 \), and \( c = 6 \) into the quadratic formula is:

[tex]\[ x = \frac{-(-2) \pm \sqrt{(-2)^2 - 4(-3)(6)}}{2(-3)} \][/tex]

So, option 1 is the correct substitution.