Questions: Completely factor the expression by grouping, if possible.
10 y^3+45 y^2-2 y-9
Transcript text: Completely factor the expression by grouping, if possible.
\[
10 y^{3}+45 y^{2}-2 y-9
\]
Solution
Solution Steps
To factor the expression by grouping, we first split the expression into two groups. We then factor out the greatest common factor from each group. If the resulting binomials are the same, we can factor them out, leading to the completely factored expression.
Step 1: Group the Terms
The given expression is \(10y^3 + 45y^2 - 2y - 9\). We can group the terms as follows:
Group 1: \(10y^3 + 45y^2\)
Group 2: \(-2y - 9\)
Step 2: Factor Each Group
Factor out the greatest common factor from each group:
From Group 1: \(10y^3 + 45y^2 = 5y^2(2y + 9)\)
From Group 2: \(-2y - 9 = -1(2y + 9)\)
Step 3: Factor by Grouping
Since both groups contain the common factor \((2y + 9)\), we can factor it out:
\[
5y^2(2y + 9) - 1(2y + 9) = (2y + 9)(5y^2 - 1)
\]
Final Answer
The completely factored expression is:
\[
\boxed{(2y + 9)(5y^2 - 1)}
\]