Step 1 :

After factoring out $ 2 $ we have:

$$ 4y^{2}+10y+8 = 2 ( 2y^{2}+5y+4 ) $$

Step 2 :

Step 2: Identify constants $ a $ , $ b $ and $ c $.
$ a $ is a number in front of the $ x^2 $ term $ b $ is a number in front of the $ x $ term and $ c $ is a constant. In this case:

$$ a = 2 , b = 5 ~ \text{ and } ~ c = 4 $$

Step 3: Multiply the leading coefficient $\color{blue}{ a = 2 }$ by the constant term $\color{blue}{c = 4} $.

$$ a \cdot c = 8 $$

Step 4: Find out two numbers that multiply to $ a \cdot c = 8 $ and add to $ b = 5 $.

Step 5: All pairs of numbers with a product of $ 8 $ are:

PRODUCT = 8
1     8	-1     -8
2     4	-2     -4

Step 6: Find out which factor pair sums up to $\color{blue}{ b = 5 }$

Step 7: Because none of these pairs will give us a sum of $ \color{blue}{ 5 }$, we conclude the polynomial cannot be factored.

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