How do you add Rational Expressions when youre in University Math?

In summary, cross multiplying and then multiplying by the common denominator is a common method for solving rational expressions. It is considered less formal and may be seen as a shortcut, but it is still a valid method as long as the correct properties and axioms are used. One can also use a scientific calculator to solve these types of problems. This method is applicable in all levels of education and is based on the same principles taught in Algebra 1 and Algebra 2.
  • #1
PhysicsHelp12
58
0
Cross multiply ...
and then multiply by the common denominator...

how do you do it

do you do it in your head..by cross multiplying

or the other way

It seems like cross multiplying is less formal ...and I don't know if its 'right' to take the shortcut --since you have to do this so much

If you have more than two like with a partial fractions problem ...im obviously going to just mult/divide by the common denominator

But how do you do it in general ...
 
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  • #2
Which kind of institution makes no difference. You use the same properties and axioms with rational expressions addition no matter whether you are in college, community college, or university. Adding rational expressions? Use lowest common denominator and raise either or both rational expressions to higher terms. This is the same idea whether you have rational fractions, complex fractions, rational expressions(using variable).
 
  • #3
... in other words, what you learned in Algebra 1 and Algebra 2 still works.
 
  • #4
[tex]\frac{a}{b} + \frac{c}{d}=\frac{da + bc}{bd}[/tex]
 
  • #5
No...I no how to do it

im just wondering how you do it persoally
 
  • #6
PhysicsHelp12 said:
No...I no how to do it

im just wondering how you do it persoally

The post #4 has it correctly. If the rational expressions are composed of few enough characters, then some of us may do one of the steps in our heads, but doing steps in our heads is not a requirement. One can often use a scientific calculator efficiently after writing the rational expression before or after any simplification step. One does what one is comfortable doing as long as the correct axioms and properties are used.
 

1. How do I simplify rational expressions in university math?

In order to simplify rational expressions, you must first factor the numerator and denominator. Then, cancel out any common factors and rewrite the expression in its simplified form.

2. Can I add rational expressions with different denominators?

Yes, you can add rational expressions with different denominators by finding the lowest common denominator (LCD). Then, multiply each fraction by a suitable form of 1 to make the denominators equal and add the numerators together.

3. Is it possible to subtract rational expressions in university math?

Yes, you can subtract rational expressions by following the same steps as adding them. Find the LCD, make the denominators equal, and then subtract the numerators.

4. What is the difference between rational expressions and rational equations?

Rational expressions are simply fractions that have variables in the numerator and/or denominator. Rational equations, on the other hand, are equations that involve rational expressions and may have a variable in the denominator that needs to be solved for.

5. Can I use the distributive property when adding rational expressions?

Yes, you can use the distributive property when adding rational expressions. This can help simplify the expressions before finding the LCD and adding the numerators together.

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