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Express (4-3i)^(3) in the form (a+ib)....

Express `(4-3i)^(3)` in the form `(a+ib)`.

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To express \((4 - 3i)^3\) in the form \(a + ib\), we will use the formula for the cube of a binomial, which is given by: \[ (a - b)^3 = a^3 - b^3 - 3ab(a - b) \] ### Step 1: Identify \(a\) and \(b\) In our case, we have: - \(a = 4\) - \(b = 3i\) ### Step 2: Apply the formula Using the formula, we can expand \((4 - 3i)^3\): \[ (4 - 3i)^3 = 4^3 - (3i)^3 - 3(4)(3i)(4 - 3i) \] ### Step 3: Calculate \(4^3\) and \((3i)^3\) Calculating \(4^3\): \[ 4^3 = 64 \] Calculating \((3i)^3\): \[ (3i)^3 = 27i^3 = 27(-i) = -27i \] ### Step 4: Calculate \(3(4)(3i)\) Calculating \(3(4)(3i)\): \[ 3(4)(3i) = 36i \] ### Step 5: Substitute back into the expression Now substituting these values back into the equation: \[ (4 - 3i)^3 = 64 - (-27i) - 36i(4 - 3i) \] ### Step 6: Simplify the expression Now we simplify the expression: \[ = 64 + 27i - 36i(4 - 3i) \] Calculating \(36i(4 - 3i)\): \[ 36i \cdot 4 = 144i \] \[ 36i \cdot (-3i) = -108i^2 = 108 \quad (\text{since } i^2 = -1) \] So, \[ 36i(4 - 3i) = 144i + 108 \] ### Step 7: Substitute and combine like terms Now substituting this back into our expression: \[ (4 - 3i)^3 = 64 + 27i - (144i + 108) \] Combining like terms: \[ = 64 - 108 + (27i - 144i) \] \[ = -44 - 117i \] ### Final Result Thus, we can express \((4 - 3i)^3\) in the form \(a + ib\) as: \[ (4 - 3i)^3 = -44 - 117i \]
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