Chapter 2: Problem 50
Exer. 1-50: Solve the equation. $$ \sqrt{x+3}=\sqrt[4]{2 x+6} $$
Short Answer
Expert verified
The solutions are \(x = -1\) and \(x = -3\).
Step by step solution
01
Isolate Both Square Roots
The equation is already in a suitable form with both square roots isolated:\[\sqrt{x+3} = \sqrt[4]{2x+6}\]
02
Eliminate the Fourth Root
Raise both sides to the fourth power to eliminate the fourth root from the equation.\[\left(\sqrt{x+3}\right)^4 = \left(\sqrt[4]{2x+6}\right)^4\]
03
Simplify Both Sides
Simplify each side after raising to the appropriate powers:- The left-hand side simplifies as \((\sqrt{x+3})^4 = (x+3)^2\).- The right-hand side simplifies to \((2x+6)\).Now, the equation is:\[(x+3)^2 = 2x + 6\]
04
Expand the Square
Expand the square on the left-hand side:\[x^2 + 6x + 9 = 2x + 6\]
05
Rearrange the Equation
Move all terms to one side to form a quadratic equation:\[x^2 + 6x + 9 - 2x - 6 = 0\]This simplifies to:\[x^2 + 4x + 3 = 0\]
06
Solve the Quadratic Equation
Factor the quadratic equation:\[(x + 1)(x + 3) = 0\]This gives two potential solutions: \(x = -1\) and \(x = -3\).
07
Verify the Solutions
Check each solution in the original equation:- For \(x = -1\), \(\sqrt{-1+3} = \sqrt[4]{2(-1)+6}\) simplifies to \(\sqrt{2} = \sqrt[4]{4}\), which holds true.- For \(x = -3\), \(\sqrt{-3+3} = \sqrt[4]{2(-3)+6}\) simplifies to \(0 = 0\), which holds true.Thus, both solutions are valid.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Quadratic Equation Solving
When faced with a quadratic equation like \(x^2 + 4x + 3 = 0\), you might wonder how to find the solutions efficiently. Quadratic equations are polynomials of degree 2, which means the highest power of the variable is 2. Here's a quick breakdown of how to tackle them.
You need to look for the standard form, which is \(ax^2 + bx + c = 0\). In this case, \(a = 1\), \(b = 4\), and \(c = 3\).
To solve it, one of the most straightforward methods is factoring. If you can rewrite the quadratic equation as a product of two binomials, like \((x + 1)(x + 3) = 0\), you'll find the solutions easily.
When the equation is factored, each factor can be set to zero to solve for \(x\):
You need to look for the standard form, which is \(ax^2 + bx + c = 0\). In this case, \(a = 1\), \(b = 4\), and \(c = 3\).
To solve it, one of the most straightforward methods is factoring. If you can rewrite the quadratic equation as a product of two binomials, like \((x + 1)(x + 3) = 0\), you'll find the solutions easily.
When the equation is factored, each factor can be set to zero to solve for \(x\):
- Set \(x + 1 = 0\), giving \(x = -1\)
- Set \(x + 3 = 0\), giving \(x = -3\)
Square Root Properties
Understanding square roots is essential when solving equations that involve them. The square root of a number is a value that, when multiplied by itself, gives the original number. It is denoted by the radical symbol \(\sqrt{...}\).
For example, \(\sqrt{x+3}\) implies you are looking for a number that squares to \(x+3\). When dealing with equations where square roots appear, like in \(\sqrt{x+3} = \sqrt[4]{2x+6}\), properties of square roots allow us to manipulate and solve the equation efficiently.
Here are some key properties:
For example, \(\sqrt{x+3}\) implies you are looking for a number that squares to \(x+3\). When dealing with equations where square roots appear, like in \(\sqrt{x+3} = \sqrt[4]{2x+6}\), properties of square roots allow us to manipulate and solve the equation efficiently.
Here are some key properties:
- The square root function applies mostly to positive numbers. \(\sqrt{9} = 3\) because \(3 \times 3 = 9\).
- You can square both sides of an equation to eliminate the square root, simplifying the equation and making it easier to solve.
Factoring Techniques
Factoring is a method used to simplify expressions and solve equations, especially quadratic ones. It's like reverse multiplication: you are breaking down a complex expression into smaller, manageable parts that multiply together to form the original expression.
In our case, the quadratic equation \(x^2 + 4x + 3 = 0\) can be factored into \((x + 1)(x + 3) = 0\).
But how do you factor a quadratic polynomial?
In our case, the quadratic equation \(x^2 + 4x + 3 = 0\) can be factored into \((x + 1)(x + 3) = 0\).
But how do you factor a quadratic polynomial?
- Identify two numbers that multiply to form the constant term \(c\) and add to give the linear coefficient \(b\).
- For \(x^2 + 4x + 3\), you need numbers that multiply to \(3\) and add up to \(4\). Those numbers are \(1\) and \(3\).