Chapter 4: Problem 72
In Exercises 65-74, use the Quadratic Formula to solve the quadratic equation. $$ \frac{7}{8} x^{2}-\frac{3}{4} x+\frac{5}{16}=0 $$
Short Answer
Expert verified
The solutions of the given quadratic equation are \( x = \frac{4}{7}, \frac{5}{8} \)
Step by step solution
01
Identify a, b and c from Quadratic Equation
In the equation \(\frac{7}{8}x^2-\frac{3}{4}x+\frac{5}{16}=0\), the values of a, b, and c are: \[ a = \frac{7}{8} \] \[ b = -\frac{3}{4} \] \[ c = \frac{5}{16} \]
02
Substitute a, b and c into Quadratic Formula
Substituting a, b, and c from the given equation into the Quadratic Formula gives us \[ x = \frac{-(-\frac{3}{4}) \pm\sqrt{(-\frac{3}{4})^{2}-4*\frac{7}{8}*\frac{5}{16}}}{2 * \frac{7}{8}} \]
03
Calculate discriminant
The value under the square root in the Quadratic Formula is called the discriminant, which is \( b^{2} - 4ac \). Therefore, \[ discriminant = (-\frac{3}{4})^{2} - 4*\frac{7}{8}*\frac{5}{16} = \frac{1}{16}\]
04
Calculate the roots
Finally, replace the discriminant in the given equation, which gives us the two roots: \[ x = \frac{\frac{3}{4} \pm\sqrt{\frac{1}{16}}}{2*\frac{7}{8}} \] Calculating the above expression gives us two roots, \( x = \frac{4}{7} , \frac{5}{8} \) These are the solutions of the given quadratic equation.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Quadratic Formula
The Quadratic Formula is a powerful tool that allows us to find solutions to quadratic equations of the form \( ax^2 + bx + c = 0 \). The formula reads:
\[ x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \]
It offers a systematic method to calculate the roots of any quadratic equation, regardless of whether the roots are real or complex.
\[ x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \]
It offers a systematic method to calculate the roots of any quadratic equation, regardless of whether the roots are real or complex.
- Substitute: Begin by identifying the coefficients a, b, and c from the equation, then plug these values into the formula.
- Calculate: Perform the operations inside the formula, including the discriminant which lies under the square root sign.
- Interpret: The resulting values of x are the roots of the quadratic equation, which might be one root repeated, two real roots, or two complex roots depending on the discriminant.
Discriminant
The discriminant is a specific part of the quadratic formula, located under the square root sign, and is denoted by \( b^2 - 4ac \). It plays a crucial role in determining the nature of the roots of a quadratic equation:
- If the discriminant is positive, the equation has two distinct real roots.
- If the discriminant is zero, the equation has exactly one real root (also known as a repeated or double root).
- If the discriminant is negative, the equation has two complex roots.
Roots of Quadratic Equation
The roots of a quadratic equation are the solutions to the equation and represent the x-values where the parabola (graph of the quadratic equation) intersects the x-axis. In simpler terms, roots are the answers we get for x when the entire quadratic equation equals zero.
\[ x = \frac{\frac{3}{4} \pm \sqrt{\frac{1}{16}}}{2 * \frac{7}{8}} \]
Solving this yields the roots \( x = \frac{4}{7} \) and \( x = \frac{5}{8} \), representing the points at which the quadratic equation's graph intersects the x-axis. Understanding the roots is crucial because they often represent meaningful intercepts in real-world problems modeled by quadratic equations.
- Real Roots: Points where the parabola touches or crosses the x-axis.
- Complex Roots: Occur when the parabola does not intersect the x-axis at all, which happens when the discriminant is negative.
\[ x = \frac{\frac{3}{4} \pm \sqrt{\frac{1}{16}}}{2 * \frac{7}{8}} \]
Solving this yields the roots \( x = \frac{4}{7} \) and \( x = \frac{5}{8} \), representing the points at which the quadratic equation's graph intersects the x-axis. Understanding the roots is crucial because they often represent meaningful intercepts in real-world problems modeled by quadratic equations.