Chapter 1: Problem 51
Solve the equation by factoring. $$2 x^{2}=8$$
Short Answer
Expert verified
The solutions are \(x = 2\) and \(x = -2\).
Step by step solution
01
Rewrite the Equation
We start with the given equation \(2x^2 = 8\). We want all terms on one side of the equation. So, subtract 8 from both sides to get \(2x^2 - 8 = 0\).
02
Factor Out the Greatest Common Factor
Look at every term in the equation \(2x^2 - 8 = 0\). Notice that 2 is a common factor. Factor out 2 from each term, leaving \(2(x^2 - 4) = 0\).
03
Factor the Quadratic Expression
Now, focus on the expression inside the parentheses \(x^2 - 4\). This is a difference of squares, which can be factored as \((x - 2)(x + 2)\). So, we have \(2(x - 2)(x + 2) = 0\).
04
Set Factors to Zero
Apply the zero product property: set each factor equal to zero. So we have two equations: \(x - 2 = 0\) and \(x + 2 = 0\).
05
Solve Each Equation
Solve these simple equations. For \(x - 2 = 0\), add 2 to both sides to get \(x = 2\). For \(x + 2 = 0\), subtract 2 from both sides to get \(x = -2\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Quadratic Equations
Understanding quadratic equations is fundamental in algebra. A quadratic equation is typically written in the standard form: \[ ax^2 + bx + c = 0 \]Here the coefficients are
- \(a\): the coefficient of the term \(x^2\) (not zero),
- \(b\): the coefficient of the term \(x\),
- \(c\): the constant term.
- two real solutions,
- one real solution, or
- no real solution.
Difference of Squares
The concept of difference of squares helps in factoring specific types of quadratic expressions. A difference of squares occurs in expressions like:\[ a^2 - b^2 \]This can be factored into:\[ (a - b)(a + b) \]This pattern arises because multiplying these two binomials,
- \((a - b)(a + b) = a^2 + ab - ab - b^2\)
Zero Product Property
The zero product property is a powerful tool for solving equations. It states that:If\[ ab = 0 \]then either
- \(a = 0\),
- \(b = 0\), or
- both are zero.
- \(x - 2 = 0\) gives solution \(x = 2\), and
- \(x + 2 = 0\) gives solution \(x = -2\).
Solving Polynomial Equations
Solving polynomial equations often involves several techniques, but factoring is one of the most straightforward when applicable. The process typically includes:
- Rewriting the equation so all terms are on one side.
- Finding a common factor if it exists, and simplifying.
- Using specific factoring techniques like difference of squares for certain expressions.
- Applying the zero product property to solve the factored equation.