Chapter 10: Problem 43
Perform the indicated operations. Simplify all answers as completely as possible. Assume that all variables appearing under radical signs are nonnegative. $$(2 \sqrt{x}-3)(3 \sqrt{x}+4)$$
Short Answer
Expert verified
The simplified answer is \(6x - \text{√}{x} -12 \)
Step by step solution
01
Expand the expression
Use the distributive property (also known as the FOIL method for binomials) to expand \(\begin{aligned} \text{(first terms)} \rightarrow 2\text{√}{x} \times 3\text{√}{x} \) \(\text{(outside terms)} \rightarrow 2\text{√}{x} \times 4 \) \(\text{(inside terms)} \rightarrow -3 \times 3\text{√}{x} \) \(\text{(last terms)} \rightarrow -3 \times 4 \ \) Thus the product becomes: \(\begin{aligned} (2\text{√}{x})(3\text{√}{x}) + (2\text{√}{x})(4) + (-3)(3\text{√}{x}) + (-3)(4) \)
02
Simplify each term
Evaluate each term in the expanded expression: For the First terms: \(\begin{aligned} (2\text{√}{x})(3\text{√}{x}) = 2 \times 3 \times \text{√}{x} \times \text{√}{x} = 6x \) For the Outside terms: \(\begin{aligned} (2\text{√}{x})(4) = 8\text{√}{x} \) For the Inside terms: \(\begin{aligned} (-3)(3\text{√}{x}) = -9\text{√}{x} \) For the Last terms: \( -3 \times 4 = -12 \).
03
Combine like terms
Combine the simplified terms: \(\begin{aligned} 6x + 8\text{√}{x} - 9\text{√}{x} - 12 \) Notice that 8\text{√}{x} and -9\text{√}{x} are like terms: \( (8\text{√}{x} - 9\text{√}{x}= -\text{√}{x}) \) Then the simplified expression finally becomes: \(6x - \text{√}{x} -12 \ \)
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Distributive Property
The distributive property is a fundamental algebraic principle that allows you to multiply a single term across a sum or difference. In binomial expressions like \((2 \text{√}{x} - 3)(3 \text{√}{x} + 4)\), the property ensures each term in the first binomial is multiplied by every term in the second binomial.
In our example, it breaks down as follows:
In our example, it breaks down as follows:
- First terms: \((2\text{√}{x})(3\text{√}{x})\)
- Outside terms: \((2\text{√}{x})(4)\)
- Inside terms: \((-3)(3\text{√}{x})\)
- Last terms: \((-3)(4)\)
FOIL Method
The FOIL Method is a specific application of the distributive property for multiplying two binomials. FOIL stands for:
- First: Multiply the first terms in each binomial.
- Outside: Multiply the outer terms in the product.
- Inside: Multiply the inside terms.
- Last: Multiply the last terms in each binomial.
- First: \((2\text{√}{x})(3\text{√}{x})\)
- Outside: \((2\text{√}{x})(4)\)
- Inside: \((-3)(3\text{√}{x})\)
- Last: \((-3)(4)\)
Combining Like Terms
Combining like terms is a process of simplifying an expression by adding or subtracting the coefficients of terms that have the same variable and exponent. For our binomial product \((2 \text{√}{x} - 3)(3 \text{√}{x} + 4)\), after expansion, we get:
ewline \text{(First terms)} \((2\text{√}{x})(3\text{√}{x}) = 6x\)
\text{(Outside terms)} \((2\text{√}{x})(4) = 8\text{√}{x}\)
\text{(Inside terms)} \((-3)(3\text{√}{x}) = -9\text{√}{x}\)
\text{(Last terms)} \((-3)(4) = -12\).
Combining like terms means we group similar terms together:
ewline \text{(First terms)} \((2\text{√}{x})(3\text{√}{x}) = 6x\)
\text{(Outside terms)} \((2\text{√}{x})(4) = 8\text{√}{x}\)
\text{(Inside terms)} \((-3)(3\text{√}{x}) = -9\text{√}{x}\)
\text{(Last terms)} \((-3)(4) = -12\).
Combining like terms means we group similar terms together:
- \(6x + 8\text{√}{x} - 9\text{√}{x} - 12\)
- \(6x - \text{√}{x} - 12\)
Radicals
Radicals (also called roots) are expressions that involve a square root, cubic root, or higher-order root. In our original problem, we had radicals of \(\text{√}{x}\). When dealing with radicals:
- Multiplying two identical radicals: \(\text{√}{a} \times \text{√}{a} = a\)
- Simplify any radicals wherever possible.