Chapter 10: Problem 30
For the following problems, solve each of the quadratic equations using the method of extraction of roots. $$ y^{2}-1=0 $$
Short Answer
Expert verified
Question: Solve the quadratic equation $$y^2 - 1 = 0$$ using the method of extraction of roots.
Answer: The solutions for the quadratic equation $$y^2 - 1 = 0$$ are $$y = -1, 1$$.
Step by step solution
01
Identify the given quadratic equation
The given quadratic equation is:
$$
y^2 - 1 = 0
$$
02
Determine if the equation is a perfect square
The left side of the equation is a difference of squares. We recognize this because:
$$
y^2 - 1 = (y - 1)(y + 1)
$$
Both the terms are perfect squares and differ by a subtraction of 1.
03
Apply the difference of squares formula
Since the equation is a difference of squares, we can apply the difference of squares formula, which states that:
$$
a^2 - b^2 = (a + b)(a - b)
$$
In our case, a = y and b = 1, so the equation becomes:
$$
y^2 - 1^2 = (y + 1)(y - 1)
$$
04
Set the factors equal to zero
Now that we have factored the equation, we can set both factors equal to zero to find the solutions for y, as follows:
$$
y + 1 = 0 \text{ or } y - 1 = 0
$$
05
Solve for y
To find the solutions for y, we now solve each of the equations separately:
1. For the first equation,
$$
y + 1 = 0
$$
Subtract 1 from both sides:
$$
y = -1
$$
2. For the second equation,
$$
y - 1 = 0
$$
Add 1 to both sides:
$$
y = 1
$$
06
Write the final solution
The solutions for the quadratic equation $$y^2 - 1 = 0$$ are:
$$
y = -1, 1
$$
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Extraction of Roots
Extraction of roots is a straightforward method for solving some quadratic equations, especially when they are in a simple form, like \(x^2 = k\) where \(k\) is a constant. This method works particularly well when the equation is already factored or can be easily factored, turning one side into perfect squares. To extract the roots, follow these steps:
- First, isolate the squared term on one side of the equation.
- Next, take the square root of both sides of the equation. Remember that you must consider both the positive and negative square roots.
- This is because squaring either a positive or negative number yields a positive result, which reflects in the solution's symmetry.
Factorization
Factorization involves expressing a quadratic equation as a product of its factors. This is a key step in solving quadratic equations since it simplifies the equation to a form that makes it easier to find its roots. To factorize a quadratic, you can use different methods, but the aim is always to rewrite the quadratic in a form like \((x - p)(x - q) = 0\), where \(p\) and \(q\) are the solutions.
- If you recognize the equation as a perfect square or a difference of squares, you can apply those specific formulas.
- For a simple equation like \(y^2 - 1 = 0\), notice both \(y^2\) and \(1\) are squares.
- Recognize this format to rewrite it as \((y - 1)(y + 1)\), using the identity for the difference of squares.
- This step breaks down the original expression into simpler linear terms, which you can then solve easily to find the roots.
Difference of Squares
The 'difference of squares' is a special algebraic identity that simplifies the factorization of certain quadratic equations. This identity applies to expressions in the form \(a^2 - b^2\) and can be rewritten as \((a + b)(a - b)\). This formula is crucial in transforming quadratic equations into a factorable form.When dealing with equations like \(y^2 - 1 = 0\), we see a classic difference of squares scenario.
- Both \(y^2\) and \(1\) are perfect squares, making \(1\) equivalent to \(1^2\).
- By setting \(a = y\) and \(b = 1\), you directly apply the formula to get \((y + 1)(y - 1) = 0\).