Math Problem Statement
The table of values represents a linear function g(x), where x is the number of days that have passed and g(x) is the balance in the bank account:
xg(x)
0
$325
5
$400
10
$475
Part A: Find and interpret the slope of the function. (3 points)
Part B: Write the equation of the line in point-slope, slope-intercept, and standard forms. (3 points)
Part C: Write the equation of the line using function notation. (2 points)
Part D: What is the balance in the bank account after 12 days? (2 points)
Solution
Let's break this down step by step:
Part A: Find and interpret the slope of the function. (3 points)
The slope of a linear function represents the rate of change of the dependent variable (in this case, the bank balance ) with respect to the independent variable (the number of days).
The formula for the slope is:
Using the two points from the table:
Substitute into the slope formula:
Interpretation:
The slope is 15, which means the balance in the bank account increases by $15 per day.
Part B: Write the equation of the line in point-slope, slope-intercept, and standard forms. (3 points)
-
Point-slope form:
The point-slope form of a line is:Using the slope and the point :
Simplified:
-
Slope-intercept form:
The slope-intercept form of a line is:From the slope and the initial value , the equation is:
-
Standard form:
The standard form of a line is:Rearranging the slope-intercept form :
Multiplying through by -1:
Or:
Part C: Write the equation of the line using function notation. (2 points)
In function notation, the equation is simply:
This represents the same linear equation as in Part B but written explicitly as a function.
Part D: What is the balance in the bank account after 12 days? (2 points)
To find the balance after 12 days, substitute into the equation:
So, the balance after 12 days is $505.
Would you like any further details or clarification on any part?
5 Related Questions:
- How would the slope change if the bank balance decreased over time instead of increasing?
- What is the significance of the y-intercept in this problem?
- How can you use this model to predict the balance after 20 days?
- How do you convert between point-slope form and slope-intercept form?
- What happens to the equation if there was an initial fee, reducing the balance at the start?
Tip: The slope in a linear function always represents the rate of change, whether it's an increase or decrease.
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Math Problem Analysis
Mathematical Concepts
Linear Functions
Slope
Equation of a Line
Formulas
Slope formula: m = (g(x2) - g(x1)) / (x2 - x1)
Point-slope form: y - y1 = m(x - x1)
Slope-intercept form: y = mx + b
Standard form: Ax + By = C
Theorems
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Suitable Grade Level
Grades 8-10