Table of contents
- 0. Review of Algebra4h 16m
- 1. Equations & Inequalities3h 18m
- 2. Graphs of Equations43m
- 3. Functions2h 17m
- 4. Polynomial Functions1h 44m
- 5. Rational Functions1h 23m
- 6. Exponential & Logarithmic Functions2h 28m
- 7. Systems of Equations & Matrices4h 6m
- 8. Conic Sections2h 23m
- 9. Sequences, Series, & Induction1h 19m
- 10. Combinatorics & Probability1h 45m
1. Equations & Inequalities
The Quadratic Formula
Problem 117
Textbook Question
In Exercises 115–122, find all values of x satisfying the given conditions. y1 = x - 1, y2 = x + 4 and y1y2 = 14

1
Identify the expressions for y1 and y2 given in the problem: y1 = x - 1 and y2 = x + 4.
Substitute the expressions for y1 and y2 into the equation y1y2 = 14: (x - 1)(x + 4) = 14.
Expand the left side of the equation using the distributive property: x^2 + 4x - x - 4 = 14.
Combine like terms and set the equation to zero: x^2 + 3x - 18 = 0.
Factor the quadratic equation or use the quadratic formula to find the values of x.

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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Linear Equations
Linear equations are mathematical statements that express a relationship between two variables, typically in the form y = mx + b, where m is the slope and b is the y-intercept. In this question, y1 and y2 are linear equations representing two lines in a coordinate system. Understanding how to manipulate and solve these equations is essential for finding their intersection points.
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Product of Functions
The product of functions involves multiplying two or more functions together to create a new function. In this case, y1y2 = 14 means that the product of the two linear functions must equal 14. This concept is crucial for setting up the equation that will allow us to find the values of x that satisfy both conditions simultaneously.
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Quadratic Equations
Quadratic equations are polynomial equations of the form ax^2 + bx + c = 0, where a, b, and c are constants. When we set the product of the two linear functions equal to a constant (14), we can rearrange the equation into a quadratic form. Solving this quadratic equation will yield the values of x that satisfy the original conditions.
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