Chapter 3: Problem 11
Find all real solutions to each equation. Check your answers. $$\sqrt{x+1}=x-5$$
Short Answer
Expert verified
The only real solution is x = 8.
Step by step solution
01
- Isolate the square root
Given the equation \(\root{x+1}=x-5\), notice that the square root term is already isolated.
02
- Square both sides
Square both sides of the equation to remove the square root. \[ (\root{x+1})^2 = (x-5)^2 \] This simplifies to: \[ x + 1 = (x-5)^2 \]
03
- Expand and simplify
Expand the right side of the equation. \[ x + 1 = x^2 - 10x + 25 \] Next, move all terms to one side to set the equation to zero. \[ 0 = x^2 - 11x + 24 \]
04
- Solve the quadratic equation
The quadratic equation \(0 = x^2 - 11x + 24\) can be solved by factoring. \[ x^2 - 11x + 24 = (x-3)(x-8) \] Set each factor to zero and solve for x. \[ x-3=0 \] \[ x = 3 \] \[ x-8=0 \] \[ x = 8 \]
05
- Check the solutions
Substitute each solution back into the original equation to verify.For \( x = 3 \): \[ \root{3+1} = 3-5 \] \[ 2 eq -2 \] (False, so x = 3 is not a solution)For \( x = 8 \): \[ \root{8+1} = 8-5 \] \[ 3 = 3 \] (True, so x = 8 is a solution)
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 second-degree polynomial equation that has the form \[ ax^2 + bx + c = 0 \].
In this exercise, we arrive at the quadratic equation \[ x^2 - 11x + 24 = 0 \] after squaring both sides of the original equation and simplifying.
Quadratic equations can have two solutions, one solution, or no real solutions depending on the value of the discriminant \( D = b^2 - 4ac \). If \( D > 0 \), there are two real solutions. If \( D = 0 \), there is one real solution. If \( D < 0 \), there are no real solutions.
In our case, the quadratic equation \( x^2 - 11x + 24 = 0 \) was solved by factoring.
In this exercise, we arrive at the quadratic equation \[ x^2 - 11x + 24 = 0 \] after squaring both sides of the original equation and simplifying.
Quadratic equations can have two solutions, one solution, or no real solutions depending on the value of the discriminant \( D = b^2 - 4ac \). If \( D > 0 \), there are two real solutions. If \( D = 0 \), there is one real solution. If \( D < 0 \), there are no real solutions.
In our case, the quadratic equation \( x^2 - 11x + 24 = 0 \) was solved by factoring.
Factoring
Factoring is the process of breaking down a polynomial into simpler polynomials whose product is the original polynomial.
To factor the quadratic equation \( x^2 - 11x + 24 \), we look for two numbers that multiply to give \( 24 \) (the constant term) and add to give \( -11 \) (the linear coefficient).
These numbers are \( -3 \) and \( -8 \). Thus, we write:
\( x^2 - 11x + 24 = (x-3)(x-8) \).
After factoring, we set each factor equal to zero:
\( x-3 = 0 \), which gives \( x = 3 \), and \( x-8 = 0 \), which gives \( x = 8 \).
These are the potential solutions to the quadratic equation.
To factor the quadratic equation \( x^2 - 11x + 24 \), we look for two numbers that multiply to give \( 24 \) (the constant term) and add to give \( -11 \) (the linear coefficient).
These numbers are \( -3 \) and \( -8 \). Thus, we write:
\( x^2 - 11x + 24 = (x-3)(x-8) \).
After factoring, we set each factor equal to zero:
\( x-3 = 0 \), which gives \( x = 3 \), and \( x-8 = 0 \), which gives \( x = 8 \).
These are the potential solutions to the quadratic equation.
Checking Solutions
After obtaining the potential solutions \( x = 3 \) and \( x = 8 \), it's crucial to check whether these solutions satisfy the original equation \( \sqrt{x+1} = x-5 \).
Substituting \( x = 3 \) into the original equation gives:
\( \sqrt{3 + 1} = 3 - 5 \)
\( \sqrt{4} = -2 \)
\( 2 eq -2 \), so \( x = 3 \) is not a valid solution.
Substituting \( x = 8 \) into the original equation gives:
\( \sqrt{8 + 1} = 8 - 5 \)
\( \sqrt{9} = 3 \)
\( 3 = 3 \), so \( x = 8 \) is a valid solution.
Always remember to check your solutions in the original equation, especially when dealing with radical equations, as extraneous solutions can arise during the process.
Substituting \( x = 3 \) into the original equation gives:
\( \sqrt{3 + 1} = 3 - 5 \)
\( \sqrt{4} = -2 \)
\( 2 eq -2 \), so \( x = 3 \) is not a valid solution.
Substituting \( x = 8 \) into the original equation gives:
\( \sqrt{8 + 1} = 8 - 5 \)
\( \sqrt{9} = 3 \)
\( 3 = 3 \), so \( x = 8 \) is a valid solution.
Always remember to check your solutions in the original equation, especially when dealing with radical equations, as extraneous solutions can arise during the process.