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Use an analytic method to solve each equation in part (a). Support the solution with a graph. Then use the graph to solve the inequalities in parts (b) and (c). (a) \(\sqrt{4 x+13}=2 x-1\) (b) \(\sqrt{4 x+13}>2 x-1\) (c) \(\sqrt{4 x+13}<2 x-1\)

Short Answer

Expert verified
(a) Solution: x = 3; (b) Inequality: -1 < x < 3; (c) No solution.

Step by step solution

01

Solve the Equation

First, we solve the equation \(\sqrt{4x+13} = 2x - 1\). Begin by squaring both sides to eliminate the square root: \((\sqrt{4x + 13})^2 = (2x - 1)^2\). This simplifies to \(4x + 13 = 4x^2 - 4x + 1\). Next, rearrange the equation as \(4x^2 - 8x - 12 = 0\).
02

Simplify and Solve the Quadratic Equation

Factor the quadratic equation \(4x^2 - 8x - 12 = 0\) by dividing all terms by 4, yielding \(x^2 - 2x - 3 = 0\). Factor this into \((x-3)(x+1) = 0\). Setting each factor equal to zero gives the solutions \(x = 3\) and \(x = -1\).
03

Check the Solutions

Since we squared the equation in the first step, we must verify which solutions are valid for the original equation. Substitute \(x = 3\) into \(\sqrt{4(3) + 13} = 2(3) - 1\), which results in \(\sqrt{25} = 5\), a true statement. For \(x = -1\), \(\sqrt{4(-1) + 13} = 2(-1) - 1\) simplifies to \(\sqrt{9} = -3\), a false statement. Thus, the only valid solution is \(x = 3\).
04

Graph the Functions

Plot the functions \(y_1 = \sqrt{4x+13}\) and \(y_2 = 2x - 1\) on a graph to visually support the solution. The functions intersect at \(x = 3\), confirming this as the solution to the equation.
05

Solve the Inequality (b)

To solve \(\sqrt{4x+13} > 2x - 1\), look at the graph where \(y_1 = \sqrt{4x+13}\) is above \(y_2 = 2x - 1\). The region is for \(-1 < x < 3\).
06

Solve the Inequality (c)

Next, solve \(\sqrt{4x+13} < 2x - 1\) using the graph. This occurs where \(y_1 = \sqrt{4x+13}\) is below \(y_2 = 2x - 1\). Since the only point of intersection is \(x = 3\) and beyond that \(y_2\) does not clock \(y_1\), no solution exists for this inequality.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Quadratic Equations
Quadratic equations are mathematical expressions where the highest degree is two, meaning they include terms like \(x^2\). Solving quadratic equations is a foundational concept in algebra with several methods including factoring, the quadratic formula, completing the square, or graphing. Each method is aimed at finding the values of \(x\) that make the equation true, known as the equation's roots.

In our exercise, we initially had an equation with a square root, \(\sqrt{4x+13} = 2x - 1\). To solve this, we needed to square both sides, transforming it into a quadratic equation, \(4x^2 - 8x - 12 = 0\). This equation can be streamlined by dividing all terms by 4, resulting in \(x^2 - 2x - 3 = 0\).

We then factorized it into \((x-3)(x+1) = 0\), finding potential solutions \(x = 3\) and \(x = -1\). It is crucial, however, to verify these solutions in the original equation because the process of squaring can introduce extraneous solutions. In this case, only \(x = 3\) satisfied the original condition when substituted back. Understanding and applying the methods to solve quadratic equations is essential for handling more complex algebraic problems in future exercises.
Graphical Analysis
Graphical analysis involves using graphs to visualize and solve mathematical problems. This technique provides an intuitive way to understand functions and their solutions by plotting them on a coordinate plane. In this exercise, we graphically supported our analytic solution of the equation \(\sqrt{4x+13} = 2x - 1\) by plotting the functions \(y_1 = \sqrt{4x+13}\) and \(y_2 = 2x-1\).

When these two functions are plotted, their intersection point gives us the solution to the equation. Here, they intersect at \(x = 3\), corroborating our previously calculated solution, showing that graphical analysis can validate analytic solutions.

Graphs are also instrumental in solving inequalities, as they help identify regions where one function is greater or lesser than another. By observing where the graph of \(y_1\) is above \(y_2\), we determined the solution for \(\sqrt{4x+13} > 2x - 1\) as occurring in the range \(-1 < x < 3\). Conversely, seeing no region where \(y_1\) is below \(y_2\) confirmed no solution existed for \(\sqrt{4x+13} < 2x - 1\). Graphical analysis thus transforms abstract problems into visually accessible information.
Inequalities
Inequalities represent mathematical expressions where two values or functions are not necessarily equal, often using symbols like \(>\), \(<\), \(\geq\), or \(\leq\). Solving inequalities involves determining the range of values that satisfy the inequality, which can be efficiently done using graphical methods.

For \(\sqrt{4x+13} > 2x - 1\), the problem asked us to find values of \(x\) where the function \(\sqrt{4x+13}\), representing one side of our inequality, is greater than \(2x - 1\), the other side. By graphing, we observed that \(y_1 = \sqrt{4x + 13}\) was higher than \(y_2 = 2x - 1\) between \(x = -1\) and \(x = 3\). This reveals the solution set for this inequality.

On the other hand, for the inequality \(\sqrt{4x+13} < 2x - 1\), we found no overlapping region where \(y_1\) was below \(y_2\). Thus, there is no solution. Understanding and solving inequalities require careful consideration of where one function overtakes another, making graphical representations highly useful in identifying these regions, providing clear and concise solutions to complex mathematical situations.

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