What will come in the place of question mark (?) in following questions?
`(6sqrt5+7sqrt5)xx 3 sqrt5`= ?

Options

A. 915
B. 519
C. 951
D. None of these

Answer

To solve the expression \((6\sqrt{5} + 7\sqrt{5}) \times 3\sqrt{5}\), we will follow these steps:

### Step 1: Combine Like Terms
First, we simplify the expression inside the parentheses:
\[ 6\sqrt{5} + 7\sqrt{5} = (6 + 7)\sqrt{5} = 13\sqrt{5} \]

### Step 2: Multiply by \(3\sqrt{5}\)
Next, we multiply the result from Step 1 by \(3\sqrt{5}\):
\[ 13\sqrt{5} \times 3\sqrt{5} \]

### Step 3: Multiply the Coefficients
Now, we multiply the coefficients (the numbers in front):
\[ 13 \times 3 = 39 \]

### Step 4: Multiply the Square Roots
Next, we multiply the square roots:
\[ \sqrt{5} \times \sqrt{5} = \sqrt{5^2} = 5 \]

### Step 5: Combine the Results
Finally, we combine the results from Step 3 and Step 4:
\[ 39 \times 5 = 195 \]

Thus, the final answer is:
\[ \boxed{195} \]

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