In Exercises 109–114, find the x-intercept(s) of the graph of each equation. Use the x-intercepts to match the equation with its graph. The graphs are shown in [- 10, 10, 1] by [- 10, 10, 1] viewing rectangles and labeled (a) through (f). y = - (x + 1)2 + 4
Table of contents
- 0. Review of Algebra4h 18m
- 1. Equations & Inequalities3h 18m
- 2. Graphs of Equations1h 43m
- 3. Functions2h 17m
- 4. Polynomial Functions1h 44m
- 5. Rational Functions1h 23m
- 6. Exponential & Logarithmic Functions2h 28m
- 7. Systems of Equations & Matrices4h 5m
- 8. Conic Sections2h 23m
- 9. Sequences, Series, & Induction1h 22m
- 10. Combinatorics & Probability1h 45m
1. Equations & Inequalities
Intro to Quadratic Equations
Problem 122
Textbook Question
Find all values of x satisfying the given conditions. y1 = - x2 + 4x - 2, y2 = - 3x2 + x - 1, and y1 - y2 = 0
Verified step by step guidance1
Step 1: Start by substituting the given expressions for y1 and y2 into the equation y1 - y2 = 0. This gives: (-x^2 + 4x - 2) - (-3x^2 + x - 1) = 0.
Step 2: Simplify the equation by distributing the negative sign for y2 and combining like terms. This results in: -x^2 + 4x - 2 + 3x^2 - x + 1 = 0.
Step 3: Combine the x^2 terms, x terms, and constant terms. This simplifies to: (3x^2 - x^2) + (4x - x) + (-2 + 1) = 0, which becomes 2x^2 + 3x - 1 = 0.
Step 4: Solve the quadratic equation 2x^2 + 3x - 1 = 0 using the quadratic formula: x = (-b ± √(b^2 - 4ac)) / 2a, where a = 2, b = 3, and c = -1.
Step 5: Substitute the values of a, b, and c into the quadratic formula and simplify under the square root (discriminant) and the fraction to find the two possible solutions for x.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Quadratic Functions
Quadratic functions are polynomial functions of degree two, typically expressed in the form y = ax^2 + bx + c. They graph as parabolas, which can open upwards or downwards depending on the sign of the coefficient 'a'. Understanding the properties of these functions, such as their vertex, axis of symmetry, and roots, is essential for solving equations involving them.
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Finding Intersections
Finding the intersection of two functions involves setting them equal to each other and solving for the variable. In this case, we set y1 equal to y2 to find the values of x where the two parabolas intersect. This process often requires rearranging the equation into standard form and applying methods such as factoring, completing the square, or using the quadratic formula.
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Difference of Functions
The difference of two functions, represented as y1 - y2, is a new function that combines the outputs of y1 and y2. In this problem, we are tasked with finding where this difference equals zero, which indicates the points of intersection. Analyzing the resulting quadratic equation from this difference is crucial for determining the values of x that satisfy the given conditions.
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