Matematika Ria
Tambahkan ke favorit Tambahkan ke favorit
link Tautkan di sini
Beranda Matematika RiaBeranda








Hak cipta © 2009
MatematikaRia.com

Fractions in Algebra

You can add, subtract, multiply and divide fractions in algebra in the same way that you do in simple arithmetic.

Adding Fractions

To add fractions there is a simple rule:

adding fractions rule

(You can see why this works on the Common Denominator page).

Example:

x + 4  +  x - 3  =  (x+4)(4) + (3)(x-3)  =  4x+16 + 3x-9  =  7x+7
3 4 3 × 4 12 12

 

Subtracting Fractions

Subtracting fractions is very similar to adding, except that the + is now -

subtracting fractions

Example:

x + 2  -  x  =  (x+2)(x-2) - (x)(x)  =  x2-22 - x2  =  -4
x x - 2 x(x-2) x2 - 2x x2 - 2x

 

Multiplying Fractions

Multiplying fractions is the easiest one of all, just multiply the tops together, and the bottoms together:

Multiplying Fractions Rule

Example:

3x  ×  x  =  (3x)(x)  =  3x2  =  x2
x-2 3 3(x-2) 3(x-2) x-2

Dividing Fractions

To divide fractions, first "flip" the fraction you want to divide by, then use the same method as for multiplying:

divide fractions

Example:

3y2  ÷  y  =  3y2  ×  2  =  (3y2)(2)  =  6y2  =  6y
x+1 2 x+1 y (x+1)(y) (x+1)(y) x+1