If 20 − x = 15 , what is the value of 3 x ?

Options

A. 5
B. 10
C. 15
D. 35

Explanation

To solve the equation \(20 - x = 15\) and find the value of \(3x\), follow these steps:

### Step 1: Solve for \(x\)
Start with the equation:
\[ 20 - x = 15 \]
To isolate \(x\), subtract 20 from both sides:
\[ -x = 15 - 20 \]
This simplifies to:
\[ -x = -5 \]
Now, multiply both sides by -1 to solve for \(x\):
\[ x = 5 \]

### Step 2: Calculate \(3x\)
Now that we have the value of \(x\), we can find \(3x\):
\[ 3x = 3 \times 5 \]
Calculating this gives:
\[ 3x = 15 \]

### Final Answer
Thus, the value of \(3x\) is:
\[ \boxed{15} \]

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