Chapter 9: Problem 40
Expand and multiply. $$(x+7)^{2}$$
Short Answer
Expert verified
\((x+7)^2 = x^2 + 14x + 49\).
Step by step solution
01
Recognize the Expression Format
The expression \((x + 7)^2\) is a binomial square. A binomial square is an expression where a binomial term is multiplied by itself.
02
Apply the Binomial Theorem for Squaring
Use the formula for squaring a binomial: \((a + b)^2 = a^2 + 2ab + b^2\). Here, \(a = x\) and \(b = 7\).
03
Calculate \(a^2\)
Square \(a\), which is \(x\): \[x^2 = x \times x = x^2\]
04
Calculate \(2ab\)
Compute the product \(2ab\): \[2ab = 2 \times x \times 7 = 14x\]
05
Calculate \(b^2\)
Square \(b\), which is 7:\[b^2 = 7 \times 7 = 49\]
06
Combine the Results
Add all the calculated parts together to expand the expression: \[x^2 + 14x + 49\]
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Squaring Binomials
When faced with an expression such as \((x + 7)^2\), you're dealing with a classic example of squaring binomials. A binomial is simply an algebraic expression containing two terms, typically in the form \((a + b)\). Squaring a binomial involves multiplying the binomial by itself.
- We have \((a + b)^2\) which means \((a + b) \times (a + b)\).
- This is where the binomial theorem comes in handy, providing a formula to simplify the process.
- The formula states that \((a + b)^2 = a^2 + 2ab + b^2\).
Algebraic Expressions
An algebraic expression like \((x + 7)^2\) can seem intimidating at first glance, but understanding its components is key to mastering algebra. At its core, an algebraic expression is a mathematical phrase that includes numbers, variables, and operators, such as addition or multiplication.
- The expression \((x + 7)^2\) features a variable \(x\) and a constant 7.
- Variables like \(x\) represent unknown values and can change, whereas constants are fixed numbers.
- Algebraic expressions depend on the rules of arithmetic and algebra to combine these elements effectively.
Polynomials
Expanding \((x + 7)^2\) transforms the expression into a polynomial, a fundamental concept encompassing expressions with one or more terms. By performing the steps outlined in our solution, we go from a simple binomial to a trinomial polynomial.
- The expanded expression \(x^2 + 14x + 49\) consists of three terms.
- Each term within the polynomial represents a degree, related to the power of the variable it contains.
- The term \(x^2\) is of degree 2, \(14x\) is of degree 1, and \(49\) is a constant term of degree 0.