/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 94 Evaluate \(\sqrt{b^{2}-4 a c}\) ... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

Evaluate \(\sqrt{b^{2}-4 a c}\) for each set of values. See Section 7.3. $$ a=1, b=6, c=2 $$

Short Answer

Expert verified
The value is \(2\sqrt{7}\).

Step by step solution

01

Identify the Given Values

First, identify the values given for \(a\), \(b\), and \(c\). In this problem, we have \(a=1\), \(b=6\), and \(c=2\).
02

Substitute Values into the Formula

Substitute the given values of \(a\), \(b\), and \(c\) into the expression \(\sqrt{b^2 - 4ac}\). This results in: \(\sqrt{6^2 - 4 \times 1 \times 2}\).
03

Calculate \(b^2\)

Calculate \(b^2\) by squaring the value of \(b\): \(6^2 = 36\).
04

Calculate \(4ac\)

Compute the value of \(4ac\) by multiplying \(4\), \(a\), and \(c\): \(4 \times 1 \times 2 = 8\).
05

Subtract \(4ac\) from \(b^2\)

Subtract the result from Step 4 from the result in Step 3: \(36 - 8 = 28\).
06

Evaluate the Square Root

Find the square root of the result from Step 5: \(\sqrt{28}\).
07

Simplify the Square Root

Simplify \(\sqrt{28}\) by expressing it in terms of its factors. \(\sqrt{28} = \sqrt{4 \times 7} = \sqrt{4} \times \sqrt{7} = 2\sqrt{7}\).

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Discriminant
In quadratic expressions, the discriminant is a key component used to assess the nature of the roots of the equation. Specifically, for a quadratic equation in the standard form expression as \(ax^2 + bx + c = 0\), the discriminant is represented by \(b^2 - 4ac\).
  • If the discriminant is positive, this indicates two distinct real roots.
  • If the discriminant is zero, there is exactly one real root, also known as a repeated or double root.
  • Conversely, a negative discriminant means that there are no real roots, instead, the roots are complex numbers.
Understanding the discriminant helps one—at a glance—predict the kinds of solutions they are dealing with, whether it be real or complex numbers. So, before diving into solving a quadratic equation, evaluating this part can be quite informative.
Square Root Calculation
Calculating square roots is fundamental in simplifying quadratic expressions, especially under the discriminant.
  • To find the square root of a number \(n\), we look for a number \(m\) such that \(m^2 = n\).
  • Some numbers, like 4 or 9, are perfect squares, meaning they have integer square roots. For example, \(\sqrt{4} = 2\), because \(2^2 = 4\).
  • For numbers that are not perfect squares, like 28 in our exercise, the result will be an irrational number, which cannot be expressed as a simple fraction.
To find a satisfactory approximation or exact value of such square roots, it can be beneficial to express the number as a product of a perfect square and another number to simplify further.
Simplifying Radicals
Simplifying radicals involves rewriting a square root expression in its simplest form. This process often involves separating the radical into integer factors to streamline calculations and clarity. Consider \(\sqrt{28}\):
  • Factor 28 into its prime components or convenient products: 28 can be expressed as \(4 \times 7\).
  • Since 4 is a perfect square, it can be simplified as \(2^2\).
  • Break the square root across the multiplication: \(\sqrt{28} = \sqrt{4 \times 7} = \sqrt{4} \times \sqrt{7}\).
  • Solve for the square root of the perfect square \(\sqrt{4} = 2\), thus yielding \(2\sqrt{7}\).
Simplifying radicals helps in reducing the complexity of expressions and often makes further mathematical operations easier to manage.

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