If a number is decreased by 3, the principal square root of this difference is 5 less than the number. Find the number(s).
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
The Quadratic Formula
Problem 100
Textbook Question
In Exercises 91–100, find all values of x satisfying the given conditions.y1=6(x−32x)2,y2=5(x−32x),andy1 exceeds y2 by 6.
Verified step by step guidance1
Start by translating the condition "y1 exceeds y2 by 6" into an equation. This means that y1 is equal to y2 plus 6, so write: \(y_1 = y_2 + 6\).
Substitute the given expressions for \(y_1\) and \(y_2\) into the equation: \$6\left(\frac{2x}{x - 3}\right)^2 = 5\left(\frac{2x}{x - 3}\right) + 6$.
To simplify the equation, let \(t = \frac{2x}{x - 3}\). Rewrite the equation in terms of \(t\): \$6t^2 = 5t + 6$.
Rearrange the equation to standard quadratic form: \$6t^2 - 5t - 6 = 0$.
Solve the quadratic equation for \(t\) using the quadratic formula: \(t = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\), where \(a=6\), \(b=-5\), and \(c=-6\). After finding the values of \(t\), substitute back \(t = \frac{2x}{x - 3}\) and solve for \(x\).
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Rational Expressions
Rational expressions are fractions where the numerator and denominator are polynomials. Understanding how to simplify, manipulate, and evaluate these expressions is essential, especially when variables appear in denominators, as restrictions on the domain must be considered to avoid division by zero.
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Rationalizing Denominators
Setting Up and Solving Equations
To find values of x that satisfy a condition, translate the problem into an equation. Here, expressing 'y1 exceeds y2 by 6' as y1 = y2 + 6 allows you to set up an equation involving rational expressions, which you then solve by clearing denominators and simplifying.
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Quadratic Equations
After simplifying the equation, you often get a quadratic equation in terms of x. Knowing how to solve quadratics using factoring, completing the square, or the quadratic formula is crucial to find all possible solutions that satisfy the original problem.
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