/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 11 Express as a polynomial. $$(x-... [FREE SOLUTION] | 91Ó°ÊÓ

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Express as a polynomial. $$(x-2 y)^{3}$$

Short Answer

Expert verified
\((x - 2y)^3 = x^3 - 6x^2y + 12xy^2 - 8y^3\).

Step by step solution

01

Understand the Problem

We need to express \((x - 2y)^3\) as a polynomial. This involves expanding the binomial expression using the binomial theorem.
02

Apply the Binomial Theorem

The binomial theorem states that \((a + b)^n = \sum_{k=0}^{n} \binom{n}{k} a^{n-k} b^k\). Here, let \(a = x\), \(b = -2y\), and \(n = 3\).
03

Identify Binomial Coefficients

For \(n = 3\), the binomial coefficients are \(\binom{3}{0} = 1\), \(\binom{3}{1} = 3\), \(\binom{3}{2} = 3\), and \(\binom{3}{3} = 1\).
04

Expand Using Binomial Coefficients

We use the formula: \((x - 2y)^3 = \sum_{k=0}^{3} \binom{3}{k} x^{3-k} (-2y)^k\). We will calculate each term individually.
05

Calculate Each Term

- For \(k = 0\): \(\binom{3}{0} x^{3-0} (-2y)^0 = 1 \cdot x^3 \cdot 1 = x^3\)- For \(k = 1\): \(\binom{3}{1} x^{3-1} (-2y)^1 = 3 \cdot x^2 \cdot (-2y) = -6x^2y\)- For \(k = 2\): \(\binom{3}{2} x^{3-2} (-2y)^2 = 3 \cdot x \cdot 4y^2 = 12xy^2\)- For \(k = 3\): \(\binom{3}{3} x^{3-3} (-2y)^3 = 1 \cdot 1 \cdot -8y^3 = -8y^3\)
06

Sum the Expanded Terms

Combine all the calculated terms to form the polynomial: \(x^3 - 6x^2y + 12xy^2 - 8y^3\).

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Polynomial Expansion
Polynomial expansion involves transforming a compact expression like a binomial, into a more expanded polynomial expression. This process is key in converting an equation format that reveals all the terms involved. Consider a binomial raised to a power, such as \((x - 2y)^3\). Polynomial expansion, utilizing the binomial theorem, breaks it down to a series of terms. In this example, expansion helps by representing an initially simpler-looking binomial as a polynomial with multiple terms. To accurately expand, we apply knowledge of exponents, multiplication, and applying the binomial theorem formula.By expanding, students learn how complex relationships inside expressions form a complete polynomial. This is frequently used in algebra and precalculus mathematics to aid in understanding how similar expressions can be rewritten in expanded form.
Binomial Coefficients
Binomial coefficients are numbers that arise in the expansion of a binomial expression raised to a positive integer power. They serve as coefficients in the terms of the polynomial. For example, in the expression \((x - 2y)^3\), the binomial coefficients are derived from the entries in row three of Pascal's Triangle: 1, 3, 3, 1.These coefficients are not arbitrary numbers, they are calculated using combinations represented by \(\binom{n}{k}\), where \(n\) is the power and \(k\) indicates the specific term in question. Each coefficient dictates the distribution of a particular term in the expansion. For instance, when calculating the term for \(k = 1\), the coefficient \(\binom{3}{1} = 3\) is applied to determine its contribution to the polynomial: \(-6x^2y\). Recognizing and applying binomial coefficients correctly is vital in polynomial expansion.
Algebraic Expressions
Algebraic expressions are combinations of variables, numbers, and operations. In the process of expanding polynomials, understanding how algebraic expressions work is crucial. Each term like \(x^3\), \(-6x^2y\), \(12xy^2\), and \(-8y^3\) is an algebraic expression composed of constants, variables, and coefficients.In the expansion of \((x - 2y)^3\), you see how each term involves different algebraic expressions. The first term \(x^3\) includes a variable raised to the third power without involving 'y'. As you expand, each succeeding term involves mixing powers of 'x' and 'y', signifying that different variables interact through algebraic operations. Mastering algebraic expressions aids not only in simplification but also helps in understanding how expressions translate to real-world models.
Precalculus Mathematics
Precalculus mathematics lays the groundwork for comprehending more advanced mathematical concepts, such as calculus and algebraic structures. Polynomial expansion and manipulation of algebraic expressions are essential capabilities developed in precalculus. It involves using logical reasoning and mathematical skills to solve diverse problems and unpack complex equations.For instance, expanding \((x - 2y)^3\) demands skills in recognising patterns and applying the binomial theorem, which are foundational skills in precalculus. Such exercises enhance student proficiency in handling variables and understanding their interactions, plotting graphs, and solving equations, all of which are pivotal in advanced mathematical studies and applications.

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Most popular questions from this chapter

The distance that a car travels between the time the driver makes the decision to hit the brakes and the time the car actually stops is called the braking distance. For a certain car traveling \(v \mathrm{mi} / \mathrm{hr},\) the braking distance \(d\) (in feet) is given by \(d=v+\left(v^{2} / 20\right)\). (a) Find the braking distance when \(v\) is \(55 \mathrm{mi} / \mathrm{hr}\). (b) If a driver decides to brake 120 feet from a stop sign, how fast can the car be going and still stop by the time it reaches the sign?

The temperature \(T\) (in "C) at which water boils is related to the elevation \(h\) (in meters above sea level) by the formula $$h=1000(100-T)+580(100-T)^{2}$$ for \(95 \leq T \leq 100.\) (a) At what elevation does water boil at a temperature of \(98^{\circ} \mathrm{C} ?\) (b) The elevation of Mt. Everest is approximately 8840 meters. Estimate the temperature at which water boils at the top of this mountain. (Hint: Use the quadratic formula with \(x=100-T\).)

An airplane flying north at \(200 \mathrm{mi} / \mathrm{hr}\) passed over a point on the ground at \(2: 00 \mathrm{PM}\). Another airplane at the same altitude passed over the point at 2: 30 P.M., flying east at 400 mi/hr (see the figure). (a) If \(t\) denotes the time in hours after 2: 30 P.M., express the distance \(d\) between the airplanes in terms of \(t\) (b) At what time after 2: 30 P.M. were the airplanes 500 miles apart?

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