Math... who wants to help?

Question

Factor the trinomial 2x2 + 17x - 9 on your paper. Which of the following would be part of the factored answer?

a.(2x + 1)

b.(2x - 1)

c.(x - 9)

d.none of the above

2.is The trinomial 10x2 + 11x + 3 is prime?

a.true

b.false

3.Factor the trinomial 4x2 + 24x + 11 on your paper. Which of the following would be part of the factored answer?

a.(2x + 1)

b.(2x - 11)

c.(2x + 6)

d.The trinomial is prime.

4.is The trinomial 2x2 - 8x + 5 is prime?

a.True

b.False

5. Factor the trinomial 9x2 - 18xy + 5y2 on your paper. Which of the following would be part of the factored answer?

a.(3x + 5y)

b.(3x + y)

c.(3x - 5y)

d.The trinomial is prime.

Answer 1

1. (2x - 1)(x + 9), so b.

2. (2x + 1)(5x + 3). False.

3. (2x + 11)(2x + 1), so a.

4. True.

5. (3x  - y)(3x - 5y), so c.

Wow, it's been a long time since I've factored polynomials.

Answer 2

Well, when you have a polynomial like ax^2 + bx + c, where a, b and c are numbers, you can either factor it into smaller parts, or find out it can't be factored (is prime).

You want to break it up into parts like (dx + e)(fx + g), where:

-d*f = a  (d times f)

-d*g + e*f = b

-e*g = c

So in the first question, you have 2x^2 + 17x -9,

where a = 2, b = 17, and c = -9

2 can only be broken up into 2*1, so let d be 2 and f be 1.

so you have this:

(2x + _)(x + _)

now, -9 can either be split into -1*9 or -9*1 or -3*3.

Now, notice that b = 17, is a pretty big number, so you might guess that g = 9, which gives you:

(2x + _)(x + 9)

that leaves you with e = -1

so that you get:

(2x - 1)(x + 9)

notice that, when you multiply everything out you get:

2x*x + 18x - x -9 = 2x^2 + 17x - 9

so the answer to the first question is:

b. (2x - 1)

hope this helps, and try to use these steps to arrive at the other answers. It will take practice, but you'll never learn if everyone just gives you the answers!