Chapter 2: Problem 37
Exer. \(31-44\) : Solve by using the quadratic formula. $$ \frac{3}{2} z^{2}-4 z-1=0 $$
Short Answer
Expert verified
The solutions are \( z = \frac{4 + \sqrt{22}}{3} \) and \( z = \frac{4 - \sqrt{22}}{3} \).
Step by step solution
01
Identify the coefficients
The given quadratic equation is \( \frac{3}{2}z^2 - 4z - 1 = 0 \). Identify the coefficients: \( a = \frac{3}{2} \), \( b = -4 \), and \( c = -1 \).
02
Write the quadratic formula
The quadratic formula is given by \( z = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \). We will use this formula to find the roots of the equation.
03
Calculate the discriminant
The discriminant \( \Delta \) is calculated as \( b^2 - 4ac \). Substitute the values: \( (-4)^2 - 4\left(\frac{3}{2}\right)(-1) \). This simplifies to \( 16 + 6 = 22 \).
04
Apply the quadratic formula
Substitute \( a = \frac{3}{2} \), \( b = -4 \), and \( c = -1 \) into the quadratic formula: \( z = \frac{-(-4) \pm \sqrt{22}}{2\left(\frac{3}{2}\right)} \). This simplifies to \( z = \frac{4 \pm \sqrt{22}}{3} \).
05
Separate the two solutions
The solutions to the equation are \( z = \frac{4 + \sqrt{22}}{3} \) and \( z = \frac{4 - \sqrt{22}}{3} \). These are the two roots of the quadratic equation.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Quadratic Equation
A quadratic equation is a polynomial equation of degree two. It is typically written in the standard form: \[ ax^2 + bx + c = 0 \] where:
- \( a \) is the coefficient of \( x^2 \) (the leading coefficient),
- \( b \) is the coefficient of \( x \) (the linear coefficient),
- \( c \) is the constant term.
Discriminant
The discriminant is a component of the quadratic formula, which helps determine the nature of the roots of a quadratic equation. It is denoted by the symbol \( \Delta \) and is calculated using the formula: \[ \Delta = b^2 - 4ac \] Notes on the discriminant:
- If \( \Delta > 0 \), the equation has two distinct real roots.
- If \( \Delta = 0 \), the equation has exactly one real root (or a repeated real root).
- If \( \Delta < 0 \), the equation has two complex roots (not real).
Roots of the Equation
The roots of a quadratic equation are the values of \( x \) that satisfy the equation, making the expression equal to zero. We can find these roots using the quadratic formula: \[ x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \] This formula is a dependable method for finding the solutions or roots of the quadratic equation when factorization is complex or impossible.For the quadratic equation \( \frac{3}{2}z^2 - 4z - 1 = 0 \), substituting the coefficients \( a = \frac{3}{2} \), \( b = -4 \), and \( c = -1 \) into the formula yields: \[ z = \frac{-(-4) \pm \sqrt{22}}{2\left(\frac{3}{2}\right)} \] This further simplifies to: \[ z = \frac{4 \pm \sqrt{22}}{3} \] Thus, the two solutions are:
- \( z = \frac{4 + \sqrt{22}}{3} \)
- \( z = \frac{4 - \sqrt{22}}{3} \)