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If 8 iz ^(3) + 12 z ^(2) - 18 z + 27i = ...

If `8 iz ^(3) + 12 z ^(2) - 18 z + 27i = 0,` then the vale of |z| is

A

`3/2`

B

`2/3`

C

`1`

D

`3/4`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the equation \( 8i z^3 + 12z^2 - 18z + 27i = 0 \) and find the value of \( |z| \), we can follow these steps: ### Step 1: Rearranging the Equation We start with the equation: \[ 8i z^3 + 12z^2 - 18z + 27i = 0 \] ### Step 2: Grouping Terms We can group the terms to factor them: \[ 8i z^3 + 12z^2 - 18z + 27i = 0 \] Let's factor out \( 4z^2 \) from the first two terms and \( 9i \) from the last two terms: \[ 4z^2(2iz + 3) + 9i(3 - 2iz) = 0 \] ### Step 3: Factoring the Equation Now we can rewrite the equation: \[ 4z^2(2iz + 3) + 9i(3 - 2iz) = 0 \] This can be rearranged to: \[ 4z^2(2iz + 3) + 9i(3 - 2iz) = 0 \] We can set each factor to zero: 1. \( 4z^2 = 0 \) 2. \( 2iz + 3 = 0 \) ### Step 4: Solving the First Factor From \( 4z^2 = 0 \): \[ z^2 = 0 \implies z = 0 \] However, we need to find \( |z| \), and \( |0| = 0 \) is not a valid solution in this context. ### Step 5: Solving the Second Factor From \( 2iz + 3 = 0 \): \[ 2iz = -3 \implies z = -\frac{3}{2i} \] To simplify this, we can multiply the numerator and denominator by \( i \): \[ z = -\frac{3i}{2i^2} = -\frac{3i}{-2} = \frac{3i}{2} \] ### Step 6: Finding the Modulus Now we need to find \( |z| \): \[ |z| = \left| \frac{3i}{2} \right| = \frac{3}{2} \] ### Conclusion Thus, the value of \( |z| \) is: \[ \boxed{\frac{3}{2}} \]
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