Chapter 6: Problem 87
Factor each trinomial completely. See Examples I through II and Section 6.2. \(49 p^{2}-7 p-2\)
Short Answer
Expert verified
(7p - 2)(7p + 1)
Step by step solution
01
Identify the form of the trinomial
The trinomial given is \(49p^2 - 7p - 2\). It is in the form \(ax^2 + bx + c\) where \(a = 49\), \(b = -7\), and \(c = -2\).
02
Apply factoring by grouping
First, we need to find two numbers whose product is \(a \cdot c = 49 \cdot (-2) = -98\) and whose sum is \(-7\). These numbers are \(-14\) and \(7\) because \(-14 \times 7 = -98\) and \(-14 + 7 = -7\).
03
Rewrite the trinomial
Use the numbers found in Step 2 to write \(-7p\) as \(-14p + 7p\). This gives us: \(49p^2 - 14p + 7p - 2\).
04
Factor by grouping
Group the terms into two pairs: \((49p^2 - 14p)\) and \((7p - 2)\). Factor out the greatest common factor from each pair: \(7p(7p - 2) + 1(7p - 2)\).
05
Factor out the common binomial
Notice that \((7p - 2)\) is common in both grouped terms. Factor \((7p - 2)\) out: \((7p - 2)(7p + 1)\). Thus, the completely factored form is \((7p - 2)(7p + 1)\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Factoring by Grouping
Factoring by grouping is a method used to factor polynomials, usually trinomials or quartic polynomials (those with four terms). The goal of this method is to rearrange and group terms in such a way that they can be factored into smaller, more manageable expressions. This technique can feel a bit like solving a puzzle, as you need to find terms that can group nicely together.
Here's how factoring by grouping generally works:
Here's how factoring by grouping generally works:
- Identify the product of the first and last coefficients in the trinomial, known as the product of extremes.
- Look for two numbers that multiply to this product and add up to the middle coefficient.
- Rewrite the middle term using these numbers to split it into two terms.
- Group the terms in pairs, looking for a common factor that can be factored out from each pair.
- Finally, factor out the common binomial to complete the process.
Algebraic Expressions
An algebraic expression is a mathematical phrase that includes numbers, variables (like \(p\)), and operation symbols. They are fundamental to algebra and help represent mathematical relationships in a concise way. These expressions can range from very simple to highly complex.
Algebraic expressions can include:
Algebraic expressions can include:
- Variables: Symbols such as \(x\), \(y\), or \(p\) that stand in for unknown values.
- Constants: Fixed numerical values.
- Coefficients: Numbers multiplying variables, showing how many times the variable is counted.
- Operators: Symbols for operations like addition (+), subtraction (-), multiplication (\(\times\)), and division (\(/\)).
Quadratic Equations
Quadratic equations are polynomial equations of degree 2, generally in the form \(ax^2 + bx + c = 0\) with \(a\), \(b\), and \(c\) as constants. They are called quadratics because "quad" refers to the square or the second power in these equations.
Key characteristics of quadratic equations include:
Key characteristics of quadratic equations include:
- U-shaped Graph: Their graph is a parabola that opens upwards or downwards.
- Roots/Solutions: Solutions are the points where the parabola intersects the x-axis. These roots can be real or complex.
- Factoring: One of the methods to solve quadratics is by factoring them into simpler expressions, descriptive of the original expression's roots.