i need help fastt =]

[heatherx0x]

i learned in class to do these math problems 32x²+16x-30 . Now that my semester of math is done i have forgotten how to do it. I need to know step by step how to solve because, i have a test coming up.

 

[galactus]

What do you want to do?. Find roots?. factor?. complete square? :? .

Do you remember the quadratic formula?. You can use it to find the zeros.

 

[heatherx0x]

i need to factor it & i have no idea where to start

 

[galactus]

I'll guide you through my technique for these. There may be easier but it

works. When the leading coefficient is not 1, you have to make some

adjustments.

Find 2 numbers which when added equal 16 and when multiplied equal,

here's the trickier part, -960. Because -30 times 32 equals -960.

If you would've just had x^2 instead of 32x^2, you could've just

used 'what two numbers when added equal 16 and when multiplied equal -

30'(that wouldn't factor anyway).

40 and -24 works. 40+(-24)=16, (40)(-24)=-960

\(\displaystyle \L\\32x^{2}+40x-24x-30\)

\(\displaystyle \L\\(32x^{2}+40x)-(24x+30)\)

Factor out:

\(\displaystyle \L\\8x(4x+5)-6(4x+5)\)

\(\displaystyle \L\\(8x-6)(4x+5)\)

You can even go a little further:

\(\displaystyle \L\\2(4x-3)(4x+5)\)

Like I said, there are other methods, this is just one way. Do you see?.

Try tackling some more like this one for practice.

 

[stapel]

i need to factor it & i have no idea where to start

So you're requesting links to online lessons so that you can learn the topic...? Please try these:

. . . . .WTAMU: Factoring Trinomials

. . . . .RegentsPrep: Factoring Trinomials whose leading coefficient is not 1

. . . . .The Math Forum: Two Methods of Factoring Quadratics

. . . . .Factoring Quadratics

Once you have learned the basic technique (so you have an idea of where to start), please attempt the exercise. If you get stuck, please reply showing all of the steps and reasoning you have tried thus far.

Thank you.

Eliz.

 

[heatherx0x]

so when doing 50x^2-55x-30 i have to look for a number that equals -1500?

still not to sure.

 

[stapel]

so when doing 50x^2-55x-30 i have to look for a number that equals -1500?

Wouldn't the first step be factoring out the 5 that is common to all three terms?

Eliz.

 

[galactus]

so when doing 50x^2-55x-30 i have to look for a number that equals -1500?

still not to sure.

Yes, and when added equal -55.......-75 and 20.

(-75)(20)=-1500 and -75+20=-55. Now you see?.

As Stapel said, you should always factor out a common factor first, if possible.

Check out the links Stapel listed. They are very good.

Factoring takes practice.

 

[heatherx0x]

after i factor out the 5 i get 10x^2-11x-6 and i have no idea where to go from there. i have done 5 out of my recquired 13 problems for the test... yikes.

 

[Denis]

after i factor out the 5 i get 10x^2-11x-6 and i have no idea where to go from there. i have done 5 out of my recquired 13 problems for the test... yikes.

Don't feel bad: that's not easily factorable.
You need to use the quadratic formula; go here:
http://www.purplemath.com/modules/quadform.htm

 

[stapel]

after i factor out the 5 i get 10x^2-11x-6 and i have no idea where to go from there.

Just follow the instructions you've been given (or else follow the methodology explained in any of the lessons provided). A good start would be to find the factors of (10)(-6) = -60 that add up to -11. (Hint: Try -15 and +4.)

Eliz.