Chapter 8: Problem 116
Factor out all common factors first including \(-1\) if the first term is negative. If an expression is prime, so indicate. $$ -r+3 r^{2}-10 $$
Short Answer
Expert verified
The expression \(-r + 3r^2 - 10\) is factored as \(-1(3r^2 - r + 10)\), and the quadratic is prime.
Step by step solution
01
Identify the Leading Coefficient
Look at the expression \( -r + 3r^2 - 10 \). The leading term here is \(-r\) because it will take precedence due to the ordering \( r^2 > r^1 > r^0 \). Since this term is negative, we need to factor out \(-1\) first to simplify our work.
02
Factor out -1
Factor \(-1\) from the entire expression: \(-1(r - 3r^2 + 10)\). Now, we will work with the expression inside the parentheses.
03
Rearrange the Terms
Rewrite the terms inside the parentheses in order of decreasing powers of \(r\): \(-1(3r^2 - r + 10)\). This makes it easier to look for any additional factoring possibilities.
04
Check for a Greatest Common Factor
Examine the new expression \(3r^2 - r + 10\) to see if there is a common factor among all terms. In this case, there is no common factor except 1.
05
Check for Factorability of the Quadratic
Attempt to factor \(3r^2 - r + 10\) using methods like splitting the middle term or applying the quadratic formula. This expression does not factor neatly into two binomials, suggesting that it may be prime.
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.
Leading Coefficient
The leading coefficient is the first coefficient you encounter when writing a polynomial in standard form, which is from highest to lowest degree. For the expression
- a leading term like \(-r\) indicates that there is a coefficient of \(-1\) in front of the variable \(r\).
- Because it is negative, the step-by-step solution advises to factor out \(-1\). This slight adjustment can significantly simplify the problem-solving process.
Common Factor
Identifying a common factor is crucial in breaking down expressions into simpler components. Consider the adjusted expression after the lead is reworked: \(3r^2 - r + 10\).
- Primarily, you'll want to check each term for shared factors.
- For this expression, there are no additional common factors present other than \(1\).
- Recognizing when the only common factor is \(1\) indicates that no further basic simplification is possible with that method.
Quadratic Expression
Quadratic expressions take the form \(ax^2 + bx + c\).These expressions are characterized by a degree of 2, meaning \(r^2\)terms are included. Each term’s cooperation is crucial for any factoring process:
- If factorable, quadratic expressions can be broken into pairs of binomials.
- In \(3r^2 - r + 10 \), because \(a, b, and c\) don't meet simple factorization conditions, other techniques may be necessary.
- These include splitting the middle term or using formulas.
Prime Expression
When an expression resists breaking down into simpler multipliers, it's termed a prime expression. Prime expressions are like indivisible numbers in mathematics, only they can't be further reduced or factored over the integers.
- Testing for primality involves checking various factorization methods.
- If none of these methods breaks the expression further, like in \(3r^2 - r + 10\), which remains unchanged through standard checks.
- The expression qualifies as prime.