Math  /  Algebra

QuestionFactorise 3x2+5x+2=(+)(x+)3 x^{2}+5 x+2=(-+)(x+)

Studdy Solution

STEP 1

What is this asking? We need to find two expressions that multiply together to give us 3x2+5x+23x^2 + 5x + 2. Watch out! Don't forget to check your answer by multiplying the factors back together!
It's super easy to make a small mistake, so checking is key!

STEP 2

1. Set up the factors
2. Find the constant terms
3. Find the x terms

STEP 3

Alright, let's **kick things off**!
We know our answer will look like (ax+b)(cx+d)(ax + b)(cx + d), where aa, bb, cc, and dd are numbers we need to **hunt down**!
Since when we multiply the first terms together we get 3x23x^2, and 33 is a **prime number** (meaning its only factors are 11 and itself), we can confidently say our factors will look like (3x+b)(x+d)(3x + b)(x + d).

STEP 4

Now, let's **crack the code** of those constant terms!
When we multiply the last terms in each factor, we should get 22.
Since 22 is also a **prime number**, its only factors are 11 and 22.
This means bb and dd could be 11 and 22 (in either order!).

STEP 5

Let's **test out** the combination (3x+1)(x+2)(3x + 1)(x + 2).
Multiplying this out gives us 3xx+3x2+1x+12=3x2+6x+x+2=3x2+7x+23x \cdot x + 3x \cdot 2 + 1 \cdot x + 1 \cdot 2 = 3x^2 + 6x + x + 2 = 3x^2 + 7x + 2.
Hmm, close, but not quite!
The xx term is 7x7x, not 5x5x.

STEP 6

Let's **flip the script** and try (3x+2)(x+1)(3x + 2)(x + 1).
Multiplying this out gives us 3xx+3x1+2x+21=3x2+3x+2x+2=3x2+5x+23x \cdot x + 3x \cdot 1 + 2 \cdot x + 2 \cdot 1 = 3x^2 + 3x + 2x + 2 = 3x^2 + 5x + 2. **Bingo!** That's exactly what we're looking for!

STEP 7

We've already found the correct factors in the previous step, but let's **dive a little deeper** into *why* this works.
Notice that the middle term, 5x5x, comes from adding the product of the outer terms (3x1=3x3x \cdot 1 = 3x) and the product of the inner terms (2x=2x2 \cdot x = 2x).
So, 3x+2x=5x3x + 2x = 5x, which **nails it**!

STEP 8

The factored form of 3x2+5x+23x^2 + 5x + 2 is (3x+2)(x+1)(3x + 2)(x + 1).

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