Simplify `5x(x + 2) + 4x`

Options

A. `5x^2+10`
B. 9x+10
C. `5x^2-14x`
D. `5x^2 + 14x`

Answer

To simplify the expression \( 5x(x + 2) + 4x \), we can follow these steps:

### Step 1: Distribute \( 5x \) in the first term
We start by distributing \( 5x \) across the terms inside the parentheses:

\[ 5x(x + 2) = 5x \cdot x + 5x \cdot 2 \]

This simplifies to:

\[ 5x^2 + 10x \]

### Step 2: Combine like terms
Now we add the \( 4x \) from the original expression to the result from Step 1:

\[ 5x^2 + 10x + 4x \]

Combine the like terms \( 10x \) and \( 4x \):

\[ 10x + 4x = 14x \]

So the expression now becomes:

\[ 5x^2 + 14x \]

### Final Result
Thus, the simplified expression is:

\[ 5x^2 + 14x \]

---