Chapter 9: Problem 131
Solve by using the Quadratic Formula. $$8 x^{2}-6 x+2=0$$
Short Answer
Expert verified
\(x = \frac{3 \, \pm \, \sqrt{7}i}{8}\)
Step by step solution
01
Identify the Coefficients
First, identify the coefficients from the quadratic equation in standard form: \(ax^2 + bx + c = 0\). For the equation \(8x^2 - 6x + 2 = 0\), the coefficients are: \(a = 8\), \(b = -6\), \(c = 2\).
02
Quadratic Formula
The quadratic formula is \(x = \frac{-b \, \pm \, \sqrt{b^2 - 4ac}}{2a}\). We will use this formula to find the values of \(x\).
03
Calculate the Discriminant
Calculate the discriminant \(\Delta\) using the formula \(\Delta = b^2 - 4ac\). Here, it is \((-6)^2 - 4 \cdot 8 \cdot 2\): \(36 - 64 = -28\).
04
Plug into the Quadratic Formula
Substitute \(a\), \(b\), and \(\Delta\) into the quadratic formula: \(x = \frac{-(-6) \, \pm \, \sqrt{-28}}{2 \cdot 8}\). This simplifies to \(x = \frac{6 \, \pm \, \sqrt{-28}}{16}\).
05
Simplify the Expression
Since \(\sqrt{-28} = \sqrt{28}i\), the expression becomes \(x = \frac{6 \, \pm \, 2\sqrt{7}i}{16}\), which simplifies further to \(x = \frac{3 \, \pm \, \sqrt{7}i}{8}\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
coefficients
In a quadratic equation, coefficients are the numerical values that multiply the variables. For example, in the quadratic equation \(8x^2 - 6x + 2 = 0\), the coefficients are essential to solving the equation using the Quadratic Formula.
Let's break it down:
Let's break it down:
- \(a\): The coefficient of \(x^2\), which is 8.
- \(b\): The coefficient of \(x\), which is -6.
- \(c\): The constant term, which is 2.
discriminant
The discriminant helps determine the nature of the roots of a quadratic equation. It's the part of the Quadratic Formula under the square root: \(\Delta = b^2 - 4ac\).
For the equation \(8x^2 - 6x + 2 = 0\):
For the equation \(8x^2 - 6x + 2 = 0\):
- First, calculate \(b^2\): \((-6)^2 = 36\).
- Next, calculate \(4ac\): \(4 \cdot 8 \cdot 2 = 64\).
- Finally, find the discriminant by subtracting \(4ac\) from \(b^2\): \(36 - 64 = -28\).
complex numbers
Complex numbers come into play when dealing with a negative discriminant. Complex numbers involve an imaginary unit represented as \(i\), where \(i\) is defined as \(\sqrt{-1}\). This means if you have \(\sqrt{-28}\), it's the same as \(\sqrt{28}i\).
In our example, the equation simplifies to:
In our example, the equation simplifies to:
- First, acknowledge \(\sqrt{-28}\) as \(\sqrt{28}i\).
- Rewrite the quadratic formula with this substitution: \(x = \frac{6 \pm \sqrt{28}i}{16}\).
- Simplify further by reducing to lowest terms: \(x = \frac{3 \pm \sqrt{7}i}{8}\).
standard form
The standard form of a quadratic equation is \(ax^2 + bx + c = 0\). It's a way to ensure all terms are on one side of the equation, set equal to zero.
For example, to solve \(8x^2 - 6x + 2 = 0\) using the Quadratic Formula, make sure it's in standard form where:
For example, to solve \(8x^2 - 6x + 2 = 0\) using the Quadratic Formula, make sure it's in standard form where:
- \(a = 8\)
- \(b = -6\)
- \(c = 2\)