Chapter 9: Problem 51
Expand and multiply. $$(2 x-4)^{2}$$
Short Answer
Expert verified
The expanded form is \(4x^2 - 16x + 16\).
Step by step solution
01
Recognize the Formula
To expand the expression \((2x - 4)^2\), recognize it as a perfect square. Recall the formula for a square of a binomial: \((a - b)^2 = a^2 - 2ab + b^2\). Here, \(a = 2x\) and \(b = 4\).
02
Apply the Formula
Substitute \(a = 2x\) and \(b = 4\) into the formula: \((2x - 4)^2 = (2x)^2 - 2(2x)(4) + (4)^2\).
03
Simplify Each Term
Calculate each term separately:- First term: \((2x)^2 = 4x^2\).- Second term: \(-2(2x)(4) = -16x\).- Third term: \((4)^2 = 16\).
04
Write the Expanded Expression
Combine the simplified terms from Step 3 to form the expanded expression: \(4x^2 - 16x + 16\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Perfect Squares
A perfect square is an expression obtained by multiplying a binomial by itself. This concept is central in algebra because it allows us to simplify expressions and solve equations easily. Consider the binomial
- When you square it, you apply the identity
- For any two terms, say \(a\) and \(b\), the formula for a perfect square is
- Applying this to the original exercise, the binomial \((2x - 4)\) is squared to become \((2x - 4)^2\).
- This means we can expand the expression using the formula:
- where \(a = 2x\) and \(b = 4\).
- For any two terms, say \(a\) and \(b\), the formula for a perfect square is
Polynomials
Polynomials are expressions composed of variables, coefficients, and the arithmetical operations of addition, subtraction, multiplication, and non-negative integer exponents. They are fundamental in algebra because they represent general forms that can be manipulated, combined, or factored in various ways.
- In our exercise, the expanded form \(4x^2 - 16x + 16\) is a polynomial of degree two, also known as a quadratic polynomial.
- Each term of the polynomial has specific components:
- The first term, \(4x^2\), is the leading term, giving the polynomial its degree.
- The middle term, \(-16x\), involves a reduction of the expression, often involving linear terms that can influence the slope or shifts in equations.
- The last term, \(16\), is a constant term that typically affects the vertical position on a graph.
Algebraic Expressions
Algebraic expressions consist of numbers, variables, and arithmetic operations, forming the basis of algebra. They can vary in complexity from simple monomials to complex polynomials.
- Understanding and manipulating them, like in the expression \((2x - 4)^2\), helps develop skills in simplification and equation solving.
- Key operations include:
- Recognizing patterns such as perfect squares.
- Using known formulas and identities for expansion.
- Applying arithmetic to simplify each step.
- Mastery of algebraic expressions lays the groundwork for higher algebraic functions and calculus. It is essential in various mathematical contexts, including analytical geometry and mathematical modeling.