Thursday

September 18, 2014

September 18, 2014

Posted by **lauren** on Wednesday, March 17, 2010 at 10:06pm.

- math -
**Reiny**, Wednesday, March 17, 2010 at 10:34pmWhat methods have you been taught?

- math -
**Anonymous**, Wednesday, March 17, 2010 at 10:49pmFACTORING

- math -
**Reiny**, Wednesday, March 17, 2010 at 11:05pmWhat methods of factoring quadratic trinomials have you been taught ?

Does decomposition ring a bell?

- math -
**Anonymous**, Wednesday, March 17, 2010 at 11:09pmno

- math -
**Reiny**, Wednesday, March 17, 2010 at 11:21pmI will do the second one for you

6x^2+5x-4

multiply the first and last coefficients,

6 x -4 = -24

now look for 2 factors of -24 which have a sum of 5, the middle term coefficient.

I think -3 and 8 will do it.

so (-3)(8) = -24 and

(-3) + (8) = 5

so we will now "decompose" the middle term of 5x into -3x + 8x

then 6x^2+5x-4

= 6x^2 - 3x + 8x - 4

Now factor it in pairs,

= 3x(2x - 1) + 4(2x - 1)

Notice that (2x - 1) is a common factor

This must always happen!

If you have found the combination for the multiplication and addition correctly you WILL HAVE A COMMON FACTOR

so

= (2x-1)(3x+4)

There are other methods, but this one seems to be a common method taught these days. Although it might seem long, it is easy to understand and if factors exist, it will always work.

**Answer this Question**

**Related Questions**

Math - I need help to set the equation up to solve a system to ensure that I get...

math - The rectangle given has a perimeter of 14 units. Find the value(s) of x ...

algebra - i have got a lot of math problems to do...if you can just help me with...

Math - I am having problems understanding how to solve problems like the ...

Math - how do you do these problems?? 5-26 2-2/9 8-2/3 4/3+6 But I can do these ...

algebra - I have a few math questions I made them just like my actual problems ...

Math Help please!! - how do you do these problems?? 5-26 2-2/9 8-2/3 4/3+6 But I...

algebra1 - could you walk-through the steps to solving this problem because I am...

Algebra - I don't get 2 math problems, if I could see how it's completed then I ...

math - kenneth has 22 math problems to do for homeworks he has 12 problems done...