Chapter 1: Problem 13
Solve the equation by completing the square. \(x^{2}+2 x-5=0\)
Short Answer
Expert verified
The solutions are \( x = -1 \pm \sqrt{6} \).
Step by step solution
01
Move the constant term to the other side
Start with the equation:\[ x^{2} + 2x - 5 = 0 \]Add 5 to both sides to isolate the zero on one side:\[ x^{2} + 2x = 5 \]
02
Find the term to complete the square
To complete the square, we need a perfect square trinomial on the left side. Take the coefficient of \(x\), divide it by 2, and square it:- Coefficient of \(x\) is 2.- \(\left(\frac{2}{2}\right)^{2} = 1\).So, you add and subtract 1 on the left side to complete the square:\[ x^{2} + 2x + 1 - 1 = 5 \]
03
Write the perfect square trinomial
Rewrite the expression as a perfect square trinomial by grouping:\[ (x^2 + 2x + 1) - 1 = 5 \]This can be rewritten as:\[ (x + 1)^{2} - 1 = 5 \]
04
Isolate the perfect square
Add 1 to both sides to isolate the perfect square:\[ (x + 1)^{2} = 6 \]
05
Solve for x using the square root property
Take the square root of both sides to solve for \(x\):\[ x + 1 = \pm \sqrt{6} \]
06
Solve for x
Subtract 1 from both sides to solve for \(x\):\[ x = -1 \pm \sqrt{6} \]
07
Conclusion
The solutions to the equation \(x^{2}+2x-5=0\) are \[ x = -1 + \sqrt{6} \] and \[ x = -1 - \sqrt{6} \].
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.
Perfect Square Trinomial
A perfect square trinomial is a special type of quadratic expression. It takes the form of \((a+b)^2 = a^2 + 2ab + b^2\),where you can see it folds out into a square expression. This kind of trinomial is called 'perfect' because it can be rewritten as the square of a binomial.The process of converting a normal quadratic expression into a perfect square trinomial involves identifying the middle term (the term with 'x') and ensuring it matches the pattern for perfect square trinomials.
- Identify the linear coefficient (the number in front of 'x').
- Divide this coefficient by 2.
- Square the result.
Quadratic Equation
Quadratic equations are polynomials that have the form\(ax^2 + bx + c = 0\),with 'a', 'b', and 'c' as coefficients. Solving these equations can seem daunting, but remember they always represent a curve known as a parabola. Completing the square is one method used to solve these equations. When no apparent or easy factorization exists, transforming the quadratic into a perfect square trinomial can make the equation easier to handle, ultimately leading us to a solution. This evolves the equation into something reminiscent of the format \((x + p)^2 = q\).In our example, the original equation \(x^2 + 2x - 5 = 0\)was a typical quadratic equation. Through completing the square, we transformed it into \((x+1)^2 = 6\),much easier to solve, paving the way for applying the square root property.
Square Root Property
The square root property is a valuable tool for solving equations that involve a squared term set equal to a constant. Once the quadratic expression is transformed into a square of a binomial, we can use the square root function to further simplify and find solutions for 'x'.In simple terms, if you have an equation like \((X)^2 = k\),you can apply the square root to both sides:\(X = \pm \sqrt{k}\).Don't forget the plus-minus symbol; it accounts for two possible solutions.In our example, once we isolated the squared term \((x + 1)^2 = 6\),we applied the square root property:
- Square root both sides.
- This gives two possible equations: \(x + 1 = \sqrt{6}\) and \(x + 1 = - \sqrt{6}\).