If `a + 3a` is 4 less than `b + 3b`, then `a - b = `

Options

A. `-4`
B. `-1`
C. `1//5`
D. `1//3`

Answer

To solve the equation given in the problem, we can follow these steps:

### Step 1: Understand the equation
We start with the statement:
\[ a + 3a \text{ is 4 less than } b + 3b \]
This can be expressed mathematically as:
\[ a + 3a = (b + 3b) - 4 \]

### Step 2: Simplify both sides
Now, simplify both sides of the equation:
- The left side becomes:
\[ a + 3a = 4a \]
- The right side becomes:
\[ b + 3b = 4b \]
Thus, we can rewrite the equation as:
\[ 4a = 4b - 4 \]

### Step 3: Rearrange the equation
Next, we rearrange the equation to isolate terms involving \( a \) and \( b \):
\[ 4a - 4b = -4 \]

### Step 4: Factor out common terms
Now, factor out the common factor on the left side:
\[ 4(a - b) = -4 \]

### Step 5: Solve for \( a - b \)
Now, divide both sides by 4 to solve for \( a - b \):
\[ a - b = \frac{-4}{4} \]
\[ a - b = -1 \]

### Final Answer
Thus, the value of \( a - b \) is:
\[ \boxed{-1} \]

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