Chapter 6: Problem 41
Solve each equation. $$ 9 y^{2}-49=0 $$
Short Answer
Expert verified
The solutions are \(y = \frac{7}{3}\) and \(y = -\frac{7}{3}\).
Step by step solution
01
Identify the Equation Type
The given equation is \(9y^{2}-49=0\). It is a quadratic equation in the standard form of \(ax^2+bx+c=0\), where \(a=9\), \(b=0\), and \(c=-49\).
02
Move the Constant to the Other Side
Rewrite the equation by moving the constant term to the other side: \(9y^2 = 49\).
03
Divide by the Coefficient of \(y^2\)
Divide both sides by 9 to isolate \(y^2\): \(y^2 = \frac{49}{9}\).
04
Apply the Square Root
Take the square root of both sides to solve for \(y\): \(y = \pm \sqrt{\frac{49}{9}}\).
05
Simplify the Square Root
Simplify \(\sqrt{\frac{49}{9}}\) by finding the square root of the numerator and the denominator separately: \(y = \pm \frac{\sqrt{49}}{\sqrt{9}}\). Since \(\sqrt{49} = 7\) and \(\sqrt{9} = 3\), we have \(y = \pm \frac{7}{3}\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Standard Form of Quadratic Equation
The standard form of a quadratic equation is expressed as \(ax^2 + bx + c = 0\). This is a fundamental structure used when dealing with quadratic equations. Each component of the equation has a specific role:
- \(a\) is the coefficient of \(x^2\), which defines the parabola's curvature.
- \(b\) is the linear coefficient, influencing the location of the vertex horizontally.
- \(c\) is the constant term, affecting the vertical position of the parabola.
Solving Quadratic Equations
Once a quadratic equation is identified, the next step is to solve it, which involves finding its roots or solutions. There are several methods to solve quadratic equations:
- Factoring involves expressing the quadratic equation as a product of two binomials. However, not all equations are easily factorable.
- The quadratic formula, \(x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\), is a reliable method for any quadratic equation.
- Completing the square makes the equation a perfect square trinomial.
Square Root Method
The square root method is a highly efficient way to solve quadratic equations, especially when the equation is in the form \(ax^2 = c\). It's suitable when there's no linear term (\(b=0\)), as seen in our problem. Here's how it works:
- First, isolate the squared term. In this equation, it begins as \(9y^2 = 49\).
- Divide both sides by the coefficient of \(y^2\) (which is 9 in this case) to obtain \(y^2 = \frac{49}{9}\).
- Apply the square root to both sides to solve for \(y\). This results in: \(y = \pm \sqrt{\frac{49}{9}}\).
- Simplify the square root by separately finding the square roots of the numerator and the denominator: \(y = \pm \frac{7}{3}\).