/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 99 Find all real solutions of the e... [FREE SOLUTION] | 91Ó°ÊÓ

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Find all real solutions of the equation. $$2 x+\sqrt{x+1}=8$$

Short Answer

Expert verified
The real solution is \(x = 3\).

Step by step solution

01

Isolate the Square Root

To simplify the problem, let's first isolate the square root term. We begin by moving the linear term, \(2x\), to the other side of the equation:\[\sqrt{x+1} = 8 - 2x.\]
02

Square Both Sides

Next, eliminate the square root by squaring both sides of the equation. Be careful to square the entire right side as a whole:\[(\sqrt{x+1})^2 = (8 - 2x)^2.\]This simplifies to:\[x+1 = (8-2x)^2 = 64 - 32x + 4x^2.\]
03

Rearrange into a Quadratic Equation

Now, rearrange the terms to form a quadratic equation:\[4x^2 - 32x + 64 - x - 1 = 0.\]Simplifying gives:\[4x^2 - 33x + 63 = 0.\]
04

Solve the Quadratic Equation

Use the quadratic formula, \(x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\), where \(a = 4\), \(b = -33\), and \(c = 63\), to find the solutions:\[x = \frac{-(-33) \pm \sqrt{(-33)^2 - 4 \cdot 4 \cdot 63}}{2 \cdot 4}.\]Calculate:\[x = \frac{33 \pm \sqrt{1089 - 1008}}{8} = \frac{33 \pm \sqrt{81}}{8} = \frac{33 \pm 9}{8}.\]Thus, the solutions are:\[x = \frac{42}{8} = 5.25 \quad \text{and} \quad x = \frac{24}{8} = 3.\]
05

Verify the Solutions

We must verify the potential solutions in the original equation to check for extraneous solutions. Starting with \(x = 3\):\[2(3) + \sqrt{3+1} = 6 + 2 = 8.\]This satisfies the original equation.Now for \(x = 5.25\):\[2(5.25) + \sqrt{5.25+1} = 10.5 + \sqrt{6.25} = 10.5 + 2.5 = 13.\]\(x = 5.25\) does not satisfy the original equation, hence it is extraneous.

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Key Concepts

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

Radical Equations
Radical equations are those that contain a variable within a root, typically a square root. To solve these types of equations, it's important to isolate the radical on one side before proceeding with further steps, such as squaring both sides.
Squaring both sides is a common technique to eliminate the square root, but it should be done carefully. This process can often introduce extraneous roots, solutions that appear valid but do not actually satisfy the original equation.
It's important to recheck potential solutions back in the original equation to ensure they work, which helps identify and exclude any extraneous solutions.
Quadratic Formula
The quadratic formula is a universal method for finding the roots of a quadratic equation of the form \(ax^2 + bx + c = 0\). It is expressed as:
  • \(x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\)
This formula is particularly useful when factoring the quadratic is not straightforward. It provides two solutions: one using the plus sign and one using the minus sign in front of the square root.
When using the quadratic formula, it's crucial to substitute the correct values for \(a\), \(b\), and \(c\), then simplify carefully to reach the two potential solutions. These solutions may still require verification to determine if they fit within the context of the original equation.
Extraneous Solutions
Extraneous solutions are extra answers that arise from the processes used to solve an equation, but do not actually satisfy the original problem. They often occur when both sides of an equation are squared, as this can introduce additional roots.
It's crucial to identify extraneous solutions by substituting each solution back into the original equation. Only those values that satisfy the equation should be considered valid solutions.
To manage extraneous solutions effectively, always keep the original context of the equation in mind and verify potential solutions thoroughly. This precautionary step ensures that you report only the true solutions to the problem at hand.

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