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Fred keeps his savings in his mattress. He began with \(\$ 1000\) from his mother and adds \(\$ 100\) each year. His total savings \(y\) after \(x\) years are given by the equation (a) \(y=1000+100 x\). (b) \(y=100+1000 x\). (c) \(y=1000+x\).

Short Answer

Expert verified
The correct formula is (a) \(y = 1000 + 100x\).

Step by step solution

01

Understand the Problem Statement

Fred's savings plan involves starting with an initial amount and then adding a fixed amount each year. We need to determine the formula that correctly represents this situation.
02

Identify the Initial Amount

Fred starts with an initial savings of \(1000\) dollars from his mother. This is a constant addition to the total savings, which should be reflected in the equation as a constant term.
03

Determine the Annual Addition

Fred adds \(100\) dollars to his savings each year. Thus, the yearly addition is represented as \(100x\), where \(x\) is the number of years. This term must be correct to model the savings over time.
04

Construct the Savings Formula

Combine the initial amount and the yearly additions to determine the correct formula. The savings after \(x\) years will be equal to the initial savings plus the annual addition: \(y = 1000 + 100x\).
05

Verify Each Option Against Construction

Check each provided option:(a) \(y = 1000 + 100x\) aligns with our constructed formula.(b) \(y = 100 + 1000x\) incorrectly adds the large amount annually.(c) \(y = 1000 + x\) incorrectly adds only \(x\), without scaling it by the yearly addition.

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Key Concepts

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

Initial Value
Every savings journey begins with a starting point, which is known as the initial value. In Fred’s case, the initial value is the $1000 he got from his mother. This initial amount is crucial as it sets the foundation for all future savings.
Think of it as the starting line in a race. Without it, you wouldn’t know where the race begins. In an equation like Fred's, the initial value is denoted by a constant term on the right side of the equation.
In equation terms, if the formula is written as \( y = 1000 + 100x \), the 1000 is our initial value. It's what you have before any extra savings are added annually. This value does not change and is a fixed figure throughout the calculation process.
Slope
In linear equations, the slope represents the rate at which one variable changes concerning another. For Fred, the slope tells us how much his savings increase each year.
Here, the slope is 100, meaning Fred saves \(100 each year. This is crucial because it shows the growth rate of his savings over time. The slope is like the incline on a hill; it dictates how steep or gradual the journey of savings is.
In Fred's savings formula \( y = 1000 + 100x \), the term 100 is the slope. It shows that every year (each increase in \( x \)), he adds \)100 to the total savings. Understanding the slope can help predict future savings and determine how long it might take to reach his savings goals.
Algebra
Algebra is the language of equations and expressions, allowing us to solve problems by making sense of patterns and relationships. For Fred’s savings problem, algebra helps us describe the relationship between time and money saved.
Using algebra, we understand how Fred's savings change over time by forming an equation. The task involves identifying parameters such as the initial amount and annual increment and representing them in a mathematical formulation.
The equation derived, \( y = 1000 + 100x \), allows us to calculate the total savings \( y \) after any given number of years \( x \). Aligned with algebraic principles, this equation forms a straightforward relationship you can use to track savings progress.
Word Problems
Word problems like Fred's savings scenario involve applying math to real-life contexts. This is often where students face challenges; however, they are great opportunities for understanding practical use.
To solve a word problem, first comprehend what’s being asked, then translate the words into a mathematical equation. Here, it involved identifying both the initial savings and the yearly increase.
Such problems test our ability to break down a narrative into simple math equations, as we did to find the solution: \( y = 1000 + 100x \). Understanding word problems means recognizing key phrases that hint at mathematical operations, such as 'each year' indicating multiplication (or the slope). By mastering these skills, you can solve any future word problem with confidence.

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