Question

Find the missing factor. 4b2 + 17b + 15 = (b + 3)( )

Answer 1

Answer:

(4b + 5)

Step-by-step explanation:

To get 4b^2 you already have b^2 if you put b  inside the second set of brackets. But that would mean you don't have 4 anywhere to get 4b^2.

So the first step has to be

(b + 3)(4b

Now look at the 15 for a moment. It is plus 15. The only way you can get a plus 15 is if both signs are plus (after the b terms) or both terms are minus.

The middle term (17b) is plus so both terms after b are plus.

(b + 3)(4b +

Now we need something that multiplies to 15. 3*5 = 15. So the term you want is 5.

(b + 3)(4b + 5)

Does the middle term work?

5*b + 3*4b = 5b + 12b = 17b

Everything looks fine.

The second factor is 17b.