Chapter 4: Problem 34
$$\text { Evaluate each expression if } x=-\frac{1}{3}, y=\frac{2}{5}, \text { and } z=\frac{5}{6} \text { . }$$ $$x^{2}-z^{2}$$
Short Answer
Expert verified
The expression evaluates to \(-\frac{7}{12}\).
Step by step solution
01
Substitute the given values into the expression
Start with the expression \(x^2 - z^2\). Substitute the values \(x = -\frac{1}{3}\) and \(z = \frac{5}{6}\) into the expression: \[\left(-\frac{1}{3}\right)^2 - \left(\frac{5}{6}\right)^2.\]
02
Calculate \(x^2\)
Determine the square of \(x = -\frac{1}{3}\):\[\left(-\frac{1}{3}\right)^2 = \frac{1}{9}.\]
03
Calculate \(z^2\)
Determine the square of \(z = \frac{5}{6}\):\[\left(\frac{5}{6}\right)^2 = \frac{25}{36}.\]
04
Subtract \(z^2\) from \(x^2\)
Subtract \(z^2\) from \(x^2\), finding the difference between the two fractions: \[\frac{1}{9} - \frac{25}{36}.\]
05
Find a common denominator
The common denominator of 9 and 36 is 36.
06
Convert \(\frac{1}{9}\) to have denominator 36
Convert \(\frac{1}{9}\) by making its denominator 36 so it can be subtracted from \(\frac{25}{36}\):\[\frac{1}{9} = \frac{4}{36}.\]
07
Perform the subtraction
Subtract the equivalent fractions: \[\frac{4}{36} - \frac{25}{36} = -\frac{21}{36}.\]
08
Simplify the fraction
Simplify \(-\frac{21}{36}\) by dividing both the numerator and the denominator by their greatest common divisor (3): \[-\frac{21}{36} = -\frac{7}{12}.\]
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.
Squaring Fractions
Squaring a fraction involves multiplying the fraction by itself. This is an important step in our example exercise where we needed to square \(x = -\frac{1}{3}\) and \(z = \frac{5}{6}\).
- When squaring a negative fraction like \(-\frac{1}{3}\), remember that the negative sign becomes positive. This is because the square of a negative number is always positive. So, \(\left(-\frac{1}{3}\right)^2 = \left(\frac{1}{3}\right)\times\left(\frac{1}{3}\right) = \frac{1}{9}\).
- For \(z = \frac{5}{6}\), squaring it involves multiplying the fraction by itself: \(\left(\frac{5}{6}\right)^2 = \frac{5}{6}\times\frac{5}{6} = \frac{25}{36}\).
Common Denominator
A common denominator is essential when adding or subtracting fractions. It ensures that fractions have the same bottom number, allowing for the operation to be performed smoothly. In the expression \(\frac{1}{9} - \frac{25}{36}\), we need a common denominator to subtract these fractions effectively.
- First, identify the least common multiple (LCM) of the denominators 9 and 36. In this scenario, 36 is the LCM.
- Adjust the fractions so they both have this common denominator. The fraction \(\frac{1}{9}\) changes to \(\frac{4}{36}\) since \(1 \times 4 = 4\) and \(9 \times 4 = 36\).
Simplifying Fractions
After performing the operation on fractions, you may need to simplify the result. Simplifying a fraction means making it as easy to understand as possible by reducing it to its lowest terms.
- In our exercise, the subtraction resulted in \(-\frac{21}{36}\).
- To simplify, identify the greatest common divisor (GCD) of 21 and 36, which is 3. Divide both the numerator and denominator by this number.
- Hence, \(-\frac{21}{36}\) simplifies to \(-\frac{7}{12}\), producing a cleaner and neater answer. Dividing by the GCD ensures you're not left with unnecessary or redundant terms.