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Which of the following complex numbers is equal to (5 + 121) - (912 - 61), for i = √-1 ?

A) - 14 - 181
B) -4-61
C) 4 +61
D) 14 + 181

1 Answer

4 votes

Final answer:

The correct answer to the given complex expression is option D) 14 + 18i, which is found by replacing i^2 with -1 and simplifying the equation.

Step-by-step explanation:

The question asks to find which of the provided complex numbers is equal to the expression (5 + 12i) - (9i^2 - 6i), where i is the imaginary unit, equal to the square root of -1. To solve for this, we must remember that i^2 = -1, which changes the expression to (5 + 12i) - (-9 - 6i). Simplifying this, we combine like terms to get the final answer which is 14 + 18i.

The steps to solve the expression are as follows:


  1. Replace i^2 with -1 to get rid of the imaginary unit's square.

  2. Simplify the expression by combining real parts and imaginary parts separately.

  3. Write down the simplified form of the complex number.

Therefore, the correct option from the given alternatives is option D) 14 + 18i.

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