Question 1099933: 10x^5+11x^4+3x^3 I have to factor by grouping and ac method please help I don’t know what I’m doing wrong
Answer by KMST(5328)   (Show Source):
You can put this solution on YOUR website! First step - take out common factors:
Now you have to factor  .
I assume you were told that you could split the middle term into two terms,
and then "factor by grouping",
finding the coefficients of the split terms as factors of  ,
where  is the coefficient of  and  is the independent term.
 and  , so  .
You want to find a pair of numbers (factors of 30)
whose product is  , and whose sum is  .
Because the product and the sum are positive,
you know that the two factors are positive.
Nice, we do not have to worry about negative numbers.
The pairs of numbers that give as a product are
 ,
 ,
 , and
 .
So, we pick  and  ,
because they add to the middle term:  .
Writing only the part to be factored,
 .
So, after all that work,
 .
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