To solve the quadratic equation \( 3(x + 4)^2 = 39 \), we can follow these steps:
-
Divide both sides by 3: \[ (x + 4)^2 = \frac{39}{3} \Rightarrow (x + 4)^2 = 13 \]
-
Take the square root of both sides: \[ x + 4 = \pm \sqrt{13} \]
-
Isolate \( x \): \[ x = -4 \pm \sqrt{13} \]
This gives us two solutions: \[ x = -4 + \sqrt{13} \quad \text{and} \quad x = -4 - \sqrt{13} \]
Thus, the solutions in simplest form are: \[ \boxed{-4 + \sqrt{13}} \quad \text{and} \quad \boxed{-4 - \sqrt{13}} \]