What values of b satisfy 3(2b + 3)2 = 36?

b = StartFraction negative 3 + 2 StartRoot 3 EndRoot Over 2 EndFraction and StartFraction negative 3 minus 2 StartRoot 3 EndRoot Over 2 EndFraction
b = StartFraction negative 3 + 2 StartRoot 3 EndRoot Over 2 EndFraction and StartFraction negative 3 minus 2 StartRoot 3 EndRoot Over 2 EndFraction
b = StartFraction 3 Over 2 EndFraction and StartFraction negative 9 Over 2 EndFraction
b = Start Fraction 9 Over 2 EndFraction and StartFraction negative 3 Over 2 EndFraction

1 answer

Let's solve the equation \( 3(2b + 3)^2 = 36 \).

First, we can simplify the equation by dividing both sides by 3:

\[ (2b + 3)^2 = \frac{36}{3} \]

This simplifies to:

\[ (2b + 3)^2 = 12 \]

Next, we take the square root of both sides:

\[ 2b + 3 = \sqrt{12} \quad \text{or} \quad 2b + 3 = -\sqrt{12} \]

Since \(\sqrt{12} = 2\sqrt{3}\), we can rewrite the equations as:

  1. \(2b + 3 = 2\sqrt{3}\)
  2. \(2b + 3 = -2\sqrt{3}\)

Now, we will solve for \(b\) in both cases.

Solving the first equation:

\[ 2b + 3 = 2\sqrt{3} \] Subtract 3 from both sides:

\[ 2b = 2\sqrt{3} - 3 \] Divide by 2:

\[ b = \frac{2\sqrt{3} - 3}{2} \]

Solving the second equation:

\[ 2b + 3 = -2\sqrt{3} \] Subtract 3 from both sides:

\[ 2b = -2\sqrt{3} - 3 \] Divide by 2:

\[ b = \frac{-2\sqrt{3} - 3}{2} \]

Thus, the solutions for \(b\) are:

\[ b = \frac{2\sqrt{3} - 3}{2} \quad \text{and} \quad b = \frac{-2\sqrt{3} - 3}{2} \]

These solutions correspond to the values provided in the options given. To match these expressions to a simplified format, we can write them as:

  • \(b = \frac{-3 + 2\sqrt{3}}{2}\)
  • \(b = \frac{-3 - 2\sqrt{3}}{2}\)

These match to the first suggested option:

\[ b = \frac{-3 + 2\sqrt{3}}{2} \text{ and } b = \frac{-3 - 2\sqrt{3}}{2} \]

Therefore, the final answer that satisfies the equation is:

\(\boxed{b = \frac{-3 + 2\sqrt{3}}{2} \text{ and } b = \frac{-3 - 2\sqrt{3}}{2}}\)