Dividing algebraic expressions

drunken_munky52

Text and Tests 1A Q14 part i)

Divide:

x^2 - 2x^2 + 2x - 4

By:

x^2 + 2

It says try this via the old school long devision way, but when I try it, it goes pear shaped, because I cant subtract 2x from 2x^2... it makes no sense.

Can anyone tell me what Im doing wrong or tell me how to do this simple thing?

Hammer Archer

You can simplify the equation to be divided (ie x^2 - 2x^2 + 2x - 4) by subtracting 2x^2 from x^2 and then dividing the resulting equation by x^2 + 2

drunken_munky52

Hammer Archer wrote: »

You can simplify the equation to be divided (ie x^2 - 2x^2 + 2x - 4) by subtracting 2x^2 from x^2 and then dividing the resulting equation by x^2 + 2

Hey thanks, but I made a mistake:

x^2 - 2x^2 + 2x - 4

Should have read:

x^3 - 2x^2 + 2x - 4

With the x^3 at the start of the equation now what do I do?

drunken_munky52

Think I cracked it:

Rearranged:

x^2 - 2x^2 + 2x - 4

As:

x^2 + 2x - 2x^2 - 4

It worked out as:

x - 2

RoundTower

yeah you got it right

red_fox

When trying to subtract 2x from -2x^2 you simply get -2x^2-2x.

It should start something like this (it's nice to keep all similar powers of x in a single column):

       __x___________
x^2+2 /x^3-2x^2+2x-4
     -(x^3     +2x)
     --------------
         0-2x^2+ 0-4  

The way you did it won't always work.