Showing posts with label Factoring. Show all posts
Showing posts with label Factoring. Show all posts

Monday, April 21, 2014

Saturday, November 23, 2013

3v%5E2-4v%2B1=0 
We'll use grouping - there are many ways...but grouping works well for this problem 
3v%5E2-3v-v%2B1=0 
3v%28v-1%29-%28v-1%29=0 
%283v-1%29%28v-1%29 
3v-1=0 
or 
v-1=0 
which leads to 
v=1/3 
or v=1

Sunday, October 13, 2013

Factor: 15y^2+8y+1

since 3*5=15 and 3+5=8...


15y^2+8y+1=
15y^2+3y+5y+1=
(15y^2+3y)+(5y+1)=
3y(5y+1)+1(5y+1)=
(3y+1)(5y+1)

Tuesday, August 13, 2013

Thursday, August 1, 2013

factor: x3 - 12x2 + 48x - 64

x3 - 12x2 + 48x - 64 =
x3-64 -12x(x-4)=
(x-4)(x2+4x+16)-12x(x-4)=
(x-4)(x2-8x+16)=
(x-4)3 

:)

Wednesday, July 31, 2013

±√324 - how do you solve this


A method of extracting roots is to use the factorization of a number (by successively dividing out primes until the number is manageable) 
factoring 324... 
324=2*162=
2^2*81=2^2*9^2 

so that 324 = (2*9)^2 = 18^2 

therefore the square root of 324 is 18 
±√324 = ±18

:)

Wednesday, July 17, 2013

solve: 8x^2-3=2x

8x^2-3=2x 
8x^2-2x-3=0 
8x^2+4x-6x-3=0 
(8x^2+4x)-(6x+3)=0 
4x(2x+1)-3(2x+1)=0 
(4x-3)(2x+1)=0 

x=3/4 or x=-1/2

Saturday, July 6, 2013

Monday, June 24, 2013

How do you factor: 2x^2+ xy- y^2+ 3x+ 1

2x^2+ xy- y^2+ 3x+1= 

(2x-y)(x+y)+3x+1= 

(2x-y)(x+y)+2x+x+1= 

(2x-y)(x+y)+(2x-y)+(x+y+1)= 
(2x-y)(x+y+1)+(x+y+1)= 

(2x-y+1)(x+y+1) 


:)

Wednesday, June 19, 2013

Factor: 4x^2 - 16x - 9

4x^2-16x-9=0 


4x^2 - 16x = 9 
4(x^2-4x)=9 

4(x^2-4x+4)=9+4(4) 
4(x-2)^2=25 
(x-2)^2=25/4 

x-2=5/2
2x-4=5
2x-9=0 
or 

x-2=-5/2
2x-4=-5
2x+1=1 


(2x-9)(2x+1)=0

Tuesday, May 7, 2013

one of my posts on Algebra.com


Solve: 231=7(x+8)x

231=7(x+8)x
the 231 seems large, so we look for a way to simplify - and it turns out to be a multiple of 7:

7%2A33=7%2A%28x%2B8%29x

using cancellation and rearranging terms we get the following:
x%5E2%2B8x=33

x%5E2%2B8x-33=0

Notice that 11+(-3)=8 and (11)(-3)=-33 so we'll use them in our grouping:

x%5E3%2B11x-3x-33=0


x%28x%2B11%29-3%28x%2B11%29=0

%28x-3%29%28x%2B11%29=0

which has solutions

x=3 and x=-11

:)