/*! 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 Consider the expression $$ \... [FREE SOLUTION] | 91Ó°ÊÓ

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Consider the expression $$ \frac{5.4+3.2(x-2.8)}{1.2}-2.3 $$ a. Use the order of operations to find the value of the expression if \(x=7.2\). b. Set the expression equal to \(3.8\). Solve for \(x\) by undoing the sequence of operations you listed in 1la.

Short Answer

Expert verified
a. The value is approximately 13.9333. b. When the expression equals 3.8, \( x = 3.4 \).

Step by step solution

01

Substitute x in the Expression

Substitute the value of \( x = 7.2 \) into the expression. The expression becomes: \[\frac{5.4 + 3.2(7.2 - 2.8)}{1.2} - 2.3\]
02

Simplify Inside the Parentheses

Calculate the expression inside the parentheses: \( 7.2 - 2.8 = 4.4 \).So, the expression is now:\[\frac{5.4 + 3.2 \times 4.4}{1.2} - 2.3\]
03

Multiply

Perform the multiplication:\( 3.2 \times 4.4 = 14.08 \).Now update the expression:\[\frac{5.4 + 14.08}{1.2} - 2.3\]
04

Add

Add \( 5.4 + 14.08 = 19.48 \).The expression becomes:\[\frac{19.48}{1.2} - 2.3\]
05

Divide

Carry out the division:\( \frac{19.48}{1.2} = 16.2333 \) (approximate to four decimal places).Now, the expression is:\[ 16.2333 - 2.3 \]
06

Subtract

Subtract: \( 16.2333 - 2.3 = 13.9333 \)So the value of the expression is approximately 13.9333 when \( x = 7.2 \).
07

Set Expression Equal to 3.8

Set the expression equal to 3.8:\[\frac{5.4 + 3.2(x - 2.8)}{1.2} - 2.3 = 3.8\]
08

Isolate the Fraction

Add 2.3 to both sides of the equation:\[\frac{5.4 + 3.2(x - 2.8)}{1.2} = 6.1\]
09

Clear the Denominator

Multiply both sides of the equation by 1.2:\[5.4 + 3.2(x - 2.8) = 7.32\]
10

Solve for the Terms with x

Subtract 5.4 from both sides:\[3.2(x - 2.8) = 1.92\]
11

Divide to Isolate the Parentheses

Divide both sides by 3.2:\[x - 2.8 = 0.6\]
12

Solve for x

Add 2.8 to both sides:\[x = 3.4\]

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Key Concepts

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

Order of Operations
When tackling algebraic expressions, understanding the order of operations is crucial. This order ensures that everyone interprets and solves expressions in the same way. Think of it as a universal set of rules for math problems. The order of operations can be remembered by the acronym PEMDAS:
  • **Parentheses**: Solve expressions inside parentheses first. This ensures that components inside these brackets are prioritized in calculations.
  • **Exponents**: Any exponent or power is resolved next, such as squaring a number.
  • **Multiplication and Division**: These are performed from left to right, whichever comes first.
  • **Addition and Subtraction**: Like multiplication and division, these operations are performed sequentially from left to right.
As a practical application, consider this expression: \[\frac{5.4 + 3.2(x - 2.8)}{1.2} - 2.3.\]Following PEMDAS, you would first simplify inside the parentheses. Then, perform multiplication within the numerator, divide the entire expression by the denominator, and finally subtract the remaining term. This consistent procedure helps avoid mistakes and results in the correct solution.
Solving Equations
Solving equations involves finding the value of unknown variables that make the equation true. The main goal is to isolate the variable, typically "\(x\)," on one side of the equation. To do this, follow a series of inverse operations.

Inverse operations are actions that "undo" each other, such as addition and subtraction, or multiplication and division. Let's see how these principles work in a real problem:

Suppose the expression is set to equal a given number:\[\frac{5.4 + 3.2(x - 2.8)}{1.2} - 2.3 = 3.8.\]You start by reversing the subtraction of \(2.3\) by adding \(2.3\) to both sides. This leaves the fraction isolated. Next, eliminate the division by \(1.2\) by multiplying both sides by \(1.2\). Carry on by solving for terms with \(x\) through further subtraction and division.

Persevering through these steps systematically helps you reach the final solution, ensuring the equation holds true.
Algebraic Manipulation
Algebraic manipulation is a toolset of strategies used for rearranging and simplifying expressions or equations to reveal desired information, such as the value of a variable.

In this context, consider an algebraic expression set up as:\[\frac{5.4 + 3.2(x - 2.8)}{1.2}.\]To solve for \(x\), if we wanted to isolate this term, we'd use manipulation by moving other parts of the equation around. Begin by eliminating operations affecting the expression, like adding \(5.4\) or dividing by \(1.2\).

Each manipulative step, such as moving terms across the equation by adding or subtracting equal amounts from both sides, is valid as long as the balance of the equation is maintained. Multiplying or dividing by non-zero numbers is also an essential strategy for tackling coefficients attached to variables.

Through practice, algebraic manipulation becomes a powerful method to unravel complex expressions and identify variable values effortlessly. Mastering these techniques enables you to tackle more intricate problems with confidence.

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