Chapter 5: Problem 1
Solve each equation by using the Square Root Property. \(x^{2}+14 x+49=9\)
Short Answer
Expert verified
The solutions are \(x = -4\) and \(x = -10\).
Step by step solution
01
Identify the Quadratic Equation in Standard Form
The equation given is \(x^2 + 14x + 49 = 9\). Before applying the square root property, we need to express it in standard form, which involves having zero on one side of the equation. This is already in a quadratic complete square form, except for the numeric adjustment.
02
Rearrange the Equation to a Perfect Square Form
Observe that \(x^2 + 14x + 49\) is a perfect square trinomial. Recognize that it can be expressed as \((x + 7)^2 = 49\). So, adjust the equation to \((x + 7)^2 = 9+7^2 \), which remains as \((x+7)^2 = 9\).
03
Apply the Square Root Property
Using the square root property, we take the square root of both sides of the equation: \(\sqrt{(x+7)^2} = \pm\sqrt{9}\), giving us \(x+7 = \pm3\).
04
Solve the Linear Equations
Now, solve for \(x\) in two separate linear equations: \(x + 7 = 3\) and \(x + 7 = -3\).1. From \(x + 7 = 3\), subtract 7 from both sides to obtain \(x = 3 - 7 = -4\).2. From \(x + 7 = -3\), subtract 7 from both sides to obtain \(x = -3 - 7 = -10\).
05
Conclude the Solution
The solutions to the original equation \((x + 7)^2 = 9\) are \(x = -4\) and \(x = -10\). Therefore, these are the values of \(x\) which satisfy the equation.
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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 handy method for solving quadratic equations, especially when they are already in the form of a perfect square. Basically, if you have an equation of the form \[(x+a)^2 = b\]You can solve it by taking the square root of both sides. This means the expression inside the square, \[x+a\],will equal to \[ \pm \sqrt{b}\].This gives us two linear equations to solve, one for the positive square root and another for the negative square root. For example, with the equation \[(x+7)^2=9\],you apply the square root property like so:
- Take the square root of both sides: \(\sqrt{(x+7)^2} = \pm\sqrt{9}\)
- The result is two possible solutions: \((x+7)=3\) or \((x+7)=-3\)
Completing the Square
Completing the Square is a method used to transform any quadratic equation into a perfect square trinomial, which makes solving the equation using the Square Root Property straightforward. A standard quadratic equation looks like:\[ax^2 + bx + c = 0\].The goal is to rewrite this in the form of \[(x+d)^2 = e\].To complete the square, follow these steps:
- Divide all terms by \(a\) (if \(a eq 1\)) to simplify the coefficient of \(x^2\).
- Move the constant term \(c\) to the other side of the equation.
- Take half of the coefficient of \(x\), square it, and add it to both sides of the equation.
- The left side of the equation is now a perfect square trinomial, like \((x+d)^2\).
Perfect Square Trinomials
Perfect square trinomials are a special type of trinomial that can be expressed as \[(x+a)^2\].Recognizing them is crucial when solving quadratic equations, as it allows quick simplification. These trinomials have the general expanded form:\[x^2 + 2ax + a^2\].Looking at our example equation \(x^2 + 14x + 49\), this can be rewritten as the perfect square \[(x+7)^2\],since \(2(7)=14\) and \(7^2=49\).Identifying a perfect square trinomial involves checking:
- The middle term should be twice the product of the square root of the first and third terms.
- The third term should be the square of what you get in completing the square process.