Chapter 10: Problem 3
Find the exact solution(s) of each system of equations. $$ \begin{array}{l}{3 x=8 y^{2}} \\ {8 y^{2}-2 x^{2}=16}\end{array} $$
Short Answer
Expert verified
The given system has no real solutions.
Step by step solution
01
Express x in terms of y
Start with the first equation: \(3x = 8y^2\). Solve for \(x\) by dividing both sides by 3: \(x = \frac{8}{3}y^2\).
02
Substitute x in the second equation
Take the expression for \(x\) from Step 1 and substitute it into the second equation: \(8y^2 - 2\left(\frac{8}{3}y^2\right)^2 = 16\).
03
Simplify the equation
Simplify the equation from Step 2: \(8y^2 - 2\cdot\frac{64}{9}y^4 = 16\). Multiply through by 9 to clear the fraction: \(72y^2 - 128y^4 = 144\).
04
Rearrange into a polynomial equation
Rearrange the equation from Step 3: \(-128y^4 + 72y^2 - 144 = 0\). Divide the entire equation by \\(-8\) to simplify: \(16y^4 - 9y^2 + 18 = 0\).
05
Let u = y^2
Let \(u = y^2\), which transforms the equation into a quadratic form: \(16u^2 - 9u + 18 = 0\).
06
Solve the quadratic equation
Use the quadratic formula \(u = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\), with \(a = 16\), \(b = -9\), and \(c = 18\). Calculate the discriminant: \((-9)^2 - 4\cdot16\cdot18 = 81 - 1152 = -1071\). The discriminant is negative, indicating no real solutions.
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Quadratic Equations
A quadratic equation is a type of polynomial equation of the form \(ax^2 + bx + c = 0\). It includes a term with a variable raised to the second power. The standard form is characterized by three coefficients: \(a\), \(b\), and \(c\), where \(a eq 0\).Quadratic equations are central in algebra because they can model various real-world situations, like projectile motion and areas.
- The solutions to a quadratic equation are known as the roots and can be real or complex numbers.
- The number of solutions is determined by the equation's discriminant.
- These equations can be solved by factoring, using the quadratic formula, or completing the square.
Discriminant
The discriminant is a key component of the quadratic formula \(x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\). It is symbolized as \(\Delta\) and is calculated using \(b^2 - 4ac\).Understanding the discriminant helps us predict the nature and number of solutions (or roots) a quadratic equation possesses:
- A positive discriminant \((\Delta > 0)\) suggests two distinct real roots.
- A zero discriminant \((\Delta = 0)\) implies one real root (or a repeated root).
- A negative discriminant \((\Delta < 0)\) indicates that the roots are complex and no real solutions exist.
Substitution Method
The substitution method is a straightforward algebraic strategy used to solve systems of equations. It involves solving one equation for a variable and substituting that expression into another equation.Here's how it generally works:
- Take one of the equations and solve for one variable in terms of the others.
- Substitute the resulting expression into the second equation.
- This substitution reduces the system from two variables to a single variable problem.
- Solve the new, simpler equation.
- Back-substitute to find the other variable, if necessary.