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Ch. 1 - Equations and Inequalities
Blitzer - College Algebra 8th Edition
Blitzer8th EditionCollege AlgebraISBN: 9780136970514Not the one you use?Change textbook
Chapter 2, Problem 43

In Exercises 35–46, determine the constant that should be added to the binomial so that it becomes a perfect square trinomial. Then write and factor the trinomial. x223xx^2-\(\frac\)23x

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1
Identify the coefficient of the linear term in the binomial. Here, the binomial is \(x^2 - \frac{2}{3}x\), so the coefficient of \(x\) is \(-\frac{2}{3}\).
Take half of the coefficient of \(x\). Half of \(-\frac{2}{3}\) is \(-\frac{1}{3}\).
Square the result from step 2. Squaring \(-\frac{1}{3}\) gives \(\left(-\frac{1}{3}\right)^2 = \frac{1}{9}\).
Add this squared value to the original binomial to form a perfect square trinomial: \(x^2 - \frac{2}{3}x + \frac{1}{9}\).
Write the trinomial as a squared binomial using the form \((x + a)^2 = x^2 + 2ax + a^2\). Here, it factors as \(\left(x - \frac{1}{3}\right)^2\).

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

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 (a + b)^2 = a^2 + 2ab + b^2. Recognizing or creating such trinomials helps simplify factoring and solving quadratic expressions.
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Completing the Square

Completing the square involves adding a constant term to a quadratic expression to form a perfect square trinomial. This constant is found by taking half the coefficient of the linear term, squaring it, and adding it to the expression, enabling easier factoring or solving.
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Factoring Quadratic Expressions

Factoring quadratic expressions means rewriting them as a product of binomials or squares of binomials. After completing the square, the trinomial can be factored into (x + d)^2 form, which simplifies solving equations or analyzing the function.
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