Chapter 2: Problem 45
Find \(y\) given that \(x=3\). $$y=-2 x+5$$
Short Answer
Expert verified
y = -1
Step by step solution
01
- Substitute the value of x
Given the equation \( y = -2x + 5 \) and the value of \( x = 3 \), substitute 3 in place of \( x \).
02
- Simplify the expression
After substituting, the equation becomes \( y = -2(3) + 5 \). Now, simplify the expression inside the parenthesis first.
03
- Compute the product
Calculate \( -2 \times 3 \) to get \( -6 \).
04
- Add the constant term
Add the result from Step 3 to the constant term: \( -6 + 5 \). This simplifies to \( -1 \).
05
- Write down the final value of y
The value of \( y \) is therefore \( -1 \).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
substitution in algebra
Substitution in algebra is a technique where you replace a variable with a given value. This is a handy method to solve equations when one variable's value is already known. To use substitution in the provided exercise, we replaced the variable \( x \) with the value \( 3 \). By doing this, we can transform the original equation, \( y = -2x + 5 \), into a simpler expression that can be solved easily. This helps in finding the value of \( y \) corresponding to \( x = 3 \).
For example:
For example:
- Original Equation: \( y = -2x + 5 \)
- Given \(x = 3 \)
- New Equation (after substitution): \( y = -2(3) + 5 \)
simplifying expressions
Simplifying expressions is about making a mathematical expression as easy to work with as possible. This involves combining like terms and performing arithmetic operations. In the given problem, after substituting \(3\) for \( x \) in the equation \( y = -2x + 5 \), we obtained a new expression: \( y = -2(3) + 5 \).
To simplify:
To simplify:
- First, compute the product within the parenthesis: \( -2 \times 3 = -6 \).
- After this, add the constant term: \( -6 + 5 \).
- This results in: \( -1 \).
linear equations
Linear equations are algebraic equations in which each term is either a constant or the product of a constant and a single variable. These equations form straight lines when graphed on a coordinate plane. The given equation, \( y = -2x + 5 \), is a perfect example of a linear equation with \( y \) and \( x \) as its variables.
To solve a linear equation:
To solve a linear equation:
- Identify the equation format: \( y = mx + c \), where \( m \) is the slope and \( c \) is the y-intercept.
- Substitute the given value of the variable (e.g., \( x = 3 \).
- Simplify the resulting expression by performing basic arithmetic operations.