What is 20x to the 3rd + 56x to the 2nd - 12x?

Question

You have to factor. I just can't seem to get the hang of it.

Answer 1

20x^3+56x^2-12x

4x(5x^2+14x-3)

4x(5x-1)(x+3)

Answer 2

4x comes out of all those numbers
so you take out the 4x and put in front that way you can put back in later
step 1
4x( 5x^2+14x-3)
then you can go further
first look at the last number...3! what times what is 3?
only 1x3 is 3 right?
so the last numbers have to be a 1 and a 3
so far we know, now its a negative but we dont know which one will be the negative yet
4x (___x__ 1) ( ____x__ 3)
k now look at your first numer..5! what tims what is 5?
only 1x5 is 5 right?
so we know that the first two numbers are a 1 and a 5
we dont know in which order they go in regards to the 1 and3
4x ( 1x * __1)( 5x*___3)

now we put it all together with the middle number which is 14
so we know that we have a 1x3 and a 1x5 which make our end numbers
we also know that we have a negative to put with our 1or 3 in 1x3
know we have to figure out what makes 14 when added together
the answer is 5x3 equals 15
and 1x -1 equals -1
15-1 is 14
this gets easier with practise to spot
so we have to switch our 5 and our 1
4x ((5x*-1)(1x+3)

the end

Answer 3

you take out what is common in all of them: a 4 and an X

so you'll get

4x(5x^2 + 14x - 3 ) = 0