Chapter 8: Problem 47
Which one of the two equations $$ (2 x+1)^{2}=5 \text { and } x^{2}+4 x=12 $$ is more suitable for solving by the square root property? By completing the square?
Short Answer
Expert verified
Equation (2x + 1)^2 = 5 is more suitable for solving by the Square Root Property. Equation x^2 + 4x = 12 is more suitable for Completing the Square.
Step by step solution
01
Identify the format of each equation
Examine the equations provided: Equation 1: (2x + 1)^2 = 5 Equation 2: x^2 + 4x = 12
02
Recognize the Square Root Property
The Square Root Property is suitable for equations that are easily written in the form A^2 = B. Equation 1 is already in this form: (2x + 1)^2 = 5, thus it can be solved using the Square Root Property.
03
Solve using Square Root Property
To solve (2x + 1)^2 = 5, apply the square root to both sides: (2x + 1) = ±√5 Then solve for x: 2x + 1 = √5 or 2x + 1 = -√5 Thus, x = (√5 - 1)/2 or x = (-√5 - 1)/2
04
Complete the Square
To complete the square for the equation x^2 + 4x = 12, follow these steps: Rearrange the equation: x^2 + 4x - 12 = 0 Write it in the form x^2 + bx + c = 0: x^2 + 4x = 12
05
Completing the square
Add and subtract (b/2)^2 to the left hand side: x^2 + 4x + 4 = 12 + 4 This can be written as: (x + 2)^2 = 16 Now solve for x using the square root property: x+2 = ±4 So, x = 2 or x = -2
06
Determine suitable methods
Equation 1, (2x + 1)^2 = 5, is more suitable for solving by the Square Root Property. Equation 2, x^2 + 4x = 12, is more suitable for Completing the Square.
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Square Root Property
The Square Root Property is a method to solve quadratic equations and is very useful when the equation is in a specific form. Essentially, if we have an equation like \( A^2 = B \), we can solve for \( A \) by taking the square root of both sides.
For example, consider the equation \( (2x + 1)^2 = 5 \). It's already set up perfectly for this method.
It bypasses the need for more complex methods, making it a powerful tool when applicable.
For example, consider the equation \( (2x + 1)^2 = 5 \). It's already set up perfectly for this method.
- First, take the square root of both sides: \( 2x + 1 = \pm \sqrt{5} \).
- Next, solve for \( x \) by isolating it: \( 2x + 1 = \sqrt{5} \) or \( 2x + 1 = -\sqrt{5} \).
- This gives us the solutions: \( x = (\sqrt{5} - 1)/2 \) and \( x = (-\sqrt{5} - 1)/2 \).
It bypasses the need for more complex methods, making it a powerful tool when applicable.
Completing the Square
Completing the square is a method to convert a quadratic equation into a perfect square trinomial. This is helpful for solving it or for rewriting the equation in a more usable form.
For instance, consider the quadratic equation \( x^2 + 4x = 12 \). To complete the square:
For instance, consider the quadratic equation \( x^2 + 4x = 12 \). To complete the square:
- First, rearrange the equation: \( x^2 + 4x - 12 = 0 \).
- Next, move the constant term to the other side: \( x^2 + 4x = 12 \).
- Find \( (b/2)^2 \), where \( b \) is the coefficient of \( x \). Here, \( b = 4 \), so \( (4/2)^2 = 4 \).
- Add and subtract this value to the left side to form a perfect square trinomial: \( x^2 + 4x + 4 = 12 + 4 \).
- Now, rewrite the left side as a square of a binomial: \( (x + 2)^2 = 16 \).
- Finally, solve for \( x \) using the Square Root Property: \( x+2 = \pm 4 \), thus \( x = 2 \) or \( x = -2 \).
Quadratic Equations
Quadratic equations are polynomial equations of the form \( ax^2 + bx + c = 0 \) where \( a, b, \) and \( c \) are constants, and \( a eq 0 \). These equations often appear in various problem-solving scenarios, from physics to finance.
There are several methods to solve quadratic equations, such as:
Each method has its own advantages depending on the specific form of the quadratic equation. For instance:
There are several methods to solve quadratic equations, such as:
- Factoring
- Using the Quadratic Formula
- Completing the Square
- Using the Square Root Property
Each method has its own advantages depending on the specific form of the quadratic equation. For instance:
- The Quadratic Formula, \( x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \), is a universal method.
- Factoring works well if the equation can be easily broken down into simpler binomials.
- Completing the Square is handy for equations that resist factoring.
- The Square Root Property is the fastest if the equation is already in the form \( A^2 = B \).