To solve the equation \(12 = |3 + 3x|\), we need to consider the two possible cases for the absolute value expression. The first case is when the expression inside the absolute value is positive or zero, and the second case is when it is negative. We will solve for \(x\) in both scenarios and check which solutions satisfy the original equation.
Step 1: Understand the Absolute Value Equation
The given equation is:
\[
12 = |3 + 3x|
\]
An absolute value equation of the form \( |A| = B \) implies two possible equations:
\( A = B \)
\( A = -B \)
Step 2: Set Up the Two Possible Equations
For the given equation \( |3 + 3x| = 12 \), we set up the two possible equations:
\( 3 + 3x = 12 \)
\( 3 + 3x = -12 \)
Step 3: Solve the First Equation
Solve the equation \( 3 + 3x = 12 \):
\[
3 + 3x = 12
\]
Subtract 3 from both sides:
\[
3x = 12 - 3
\]
\[
3x = 9
\]
Divide both sides by 3:
\[
x = \frac{9}{3}
\]
\[
x = 3
\]
Step 4: Solve the Second Equation
Solve the equation \( 3 + 3x = -12 \):
\[
3 + 3x = -12
\]
Subtract 3 from both sides:
\[
3x = -12 - 3
\]
\[
3x = -15
\]
Divide both sides by 3:
\[
x = \frac{-15}{3}
\]
\[
x = -5
\]
Final Answer
The solutions to the equation \( 12 = |3 + 3x| \) are: