please divide x^2-x-14 by x-4

Question

lgbasallote · Answer

first rewrite it as

          ______________
x - 4 | x^2 - x - 14

now...what is x^2 divided  by x?

anonymous · Answer

x

lgbasallote · Answer

good
             x
          ______________
x - 4 | x^2 - x - 14

now we multiply x to each term of x - 4

              x
          ______________
x - 4 | x^2 - x - 14
            x^2 - 4x
         ---------------
            we subtract

can you subtract x^2 - x - (x^2 - 4x)?

anonymous · Answer

yes would it simplify to -5x?

lgbasallote · Answer

-5x? hmm remember you distribute the minus sign...

x^2 - x - x^2 - (-4x)

it becomes x^2 - x - x^2 + 4x

anonymous · Answer

ok got it so then you would subtract x from 4x?

lgbasallote · Answer

yup!!

lgbasallote · Answer

so what do you have?

anonymous · Answer

I believe  3x because the x^2s cancel out ?

lgbasallote · Answer

you got it!


              x
          ______________
x - 4 | x^2 - x - 14
            x^2 - 4x
         ---------------
                       3x

now we bring down 14

              x
          ______________
x - 4 | x^2 - x - 14
            x^2 - 4x
         ---------------
                       3x - 14

then we repeat the process...divide 3x by x

anonymous · Answer

3?

lgbasallote · Answer

good..
              x  + 3
          ______________
x - 4 | x^2 - x - 14
            x^2 - 4x
         ---------------
                       3x - 14

now multiply 3 to each term of x  - 4

anonymous · Answer

would it be 3x-12?

lgbasallote · Answer

yup!

lgbasallote · Answer

x  + 3
          ______________
x - 4 | x^2 - x - 14
            x^2 - 4x
         ---------------
                       3x - 14
                       3x - 12
                      --------
                        subtract again

anonymous · Answer

thank you so much, could you help me with solving rad72-rad50?

lgbasallote · Answer

do you know the rest for that one?

lgbasallote · Answer

remember to put the remainder :D

anonymous · Answer

do you mean the division problem is not finished

lgbasallote · Answer

haha yeah :))

lgbasallote · Answer

you still have to subtract 3x - 12 from 3x - 14

anonymous · Answer

so the final answer is -2?

lgbasallote · Answer

we still have to write -2 as a remainder to do that we write $$\frac{remainder}{divisor}$$ since our remainder is -2 and our divisor is 2x + 1 it becomse $$\frac{-2}{2x+1}$$ got it? we add that to the quotient we have so it's $$\large x + 3 - \frac{2}{2x+1}$$

lgbasallote · Answer

for more info on dividing polynomials by binomials check this out (a tutorial i made myself :D) http://openstudy.com/updates/4f9c9dace4b000ae9ed1966f now...as for your second question...please post in another question because long threads tend to be laggy

anonymous · Answer

ok thanks |dw:1336698507854:dw|