Fractions - how to find an unknown denominator

TL;DR

Learn how to solve equations with unknown denominators in fractions by finding common denominators and cross-multiplication.

Transcript

good day and welcome to the techmath channel this video is uh a response to a question that I got asked about how to work out unknown denominators in a fraction uh where you get asked say a question that look like this so say you asked what is 1 / X or an unknown number plus a quarter and this was to equal to 9 / 20 okay and how you would solve thi... Read More

Key Insights

• 😵 Working with unknown denominators in fractions involves finding a common denominator or using cross-multiplication to simplify the equation.
• 🙃 The goal is to isolate the variable by performing the necessary operations on both sides of the equation.
• 😵 The concept of cross-multiplication is a helpful technique when solving equations with unknown denominators.
• 👻 Multiplying the numerator and denominator by the same number allows for changing the fractions' denominators to a common value.
• 🍉 Simplifying the equation by combining like terms and applying the appropriate mathematical operations is important.
• ✖️ Cross-multiplication involves multiplying the numerator of one fraction by the denominator of another fraction, equating them to find the value of the unknown variable.
• 🎭 Subtraction and addition of fractions require finding a common denominator before performing the operation.

Questions & Answers

Q: How do you solve equations with unknown denominators in fractions?

To solve these equations, you need to find a common denominator and then simplify the equation by performing the necessary operations on both sides.

Q: What is the purpose of finding a common denominator?

Finding a common denominator allows you to combine fractions and perform operations on them easily.

Q: Can cross-multiplication be used to solve equations with unknown denominators?

Yes, cross-multiplication is another method to solve equations with unknown denominators. It involves multiplying diagonally across the equation to find the value of the unknown variable.

Q: How can you determine the value of the unknown variable once the equation is simplified?

Once the equation is simplified, you can either use the method of multiplying the two numbers to find the unknown variable or use cross-multiplication to solve for it directly.

Summary & Key Takeaways

• The video explains how to solve equations with unknown denominators in fractions, using examples and step-by-step instructions.

• The first step is to find a common denominator by multiplying the denominators together.

• Cross-multiplication can also be used to solve the equations.