Skip to main content
Ch. R - Review of Basic Concepts
Lial - College Algebra 13th Edition
Lial13th EditionCollege AlgebraISBN: 9780136881063당신이 사용하는 게 아니라요?교과서 변경
1장, 문제 137

Find all values of b or c that will make the polynomial a perfect square trinomial. 4z2+bz+81

검증된 단계별 안내
1
Recall that a perfect square trinomial can be written in the form \(\left( mz + n \right)^2 = m^2 z^2 + 2mnz + n^2\).
Compare the given polynomial \$4z^2 + bz + 81$ to the general form $m^2 z^2 + 2mnz + n^2$ to identify $m^2$ and $n^2$.
Since the coefficient of \(z^2\) is 4, set \(m^2 = 4\), which gives \(m = 2\) (considering the positive root for simplicity).
Since the constant term is 81, set \(n^2 = 81\), which gives \(n = 9\) (again, considering the positive root).
Use the middle term formula \$2mnz$ to find $b$: \(b = 2 \times m \times n = 2 \times 2 \times 9\), and write the value of $b$ that makes the polynomial a perfect square trinomial.

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
2m

주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Perfect Square Trinomial

A perfect square trinomial is a quadratic expression that can be factored into the square of a binomial, typically in the form (x + d)^2 = x^2 + 2dx + d^2. Recognizing this form helps identify conditions on coefficients to make the polynomial a perfect square.
추천 영상:
06:24
Solving Quadratic Equations by Completing the Square

Comparing Coefficients

To determine values of variables that make a polynomial a perfect square, compare the given polynomial's coefficients with those of the expanded perfect square form. This method allows solving for unknown coefficients by matching terms.
추천 영상:
4:32
Example 3

Factoring Quadratic Expressions

Factoring quadratics involves rewriting the expression as a product of binomials. Understanding how to factor and expand quadratics is essential to verify if a polynomial is a perfect square and to find the necessary coefficient values.
추천 영상:
06:08
Solving Quadratic Equations by Factoring