Friday

August 22, 2014

August 22, 2014

Posted by **sid** on Sunday, March 21, 2010 at 11:44am.

- algebra -
**drwls**, Sunday, March 21, 2010 at 12:08pmThe rules for numerators and denominators are different. When adding or subtracting fractions, or fractional algebraic terms, the denominators must be the same. Then, you can add or subtract the numerators while keeping the common denominator.

The reason should be obvious when you think about it. When you have a series of numbers with the same denominator x, the ratio of their sizes is the ratio of the numerators.

Thus a/x + b/x = (a+b)*(1/x) = (a+b)/x

You cannot write an analogous valid expression to justify adding denominators with a common numerator. instead, you have

x/a + x/b = x(1/a + 1/b), = x(b+a)/ab

- algebra -
**Tom**, Sunday, January 23, 2011 at 5:27pm3 4/9 x 1 4/5 show work please

**Related Questions**

Math - When adding and subtracting rational expressions, why do you need a LCD?

Algebra - Find the LCD for the given rational expressions, and convert each ...

algebra - Find the LCD for the given rational expressions, and convert each ...

Help1 - WHY rational expressions that are being added must have an LCD, but ...

algebra - Reduce to lowest terms 3x-6/x^2-4x+4 perform operation w^2-1/(w-1)2 ...

algebra - How is doing operations (adding, subtracting, multiplying, and ...

Algebra - How is doing operations (adding, subtracting, multiplying, and ...

algebra ! - i need hepl on adding and subtacting rational numbers like -7over12+...

algebra - how is doing operations, adding, subtracting, multiplying and dividing...

Math - Explain It How is adding and subtracting with money like adding and ...