$(7 - 5 i) (7 + 5 i)$
A. 14
B. 24
C. 74
D. $49 - 25 i$
E. $49 - 70 i - 25 i^{2}$

Answer

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Answer

$74$

Steps

Step 1 ：Multiply the two complex numbers using the distributive property (FOIL method): $(7 - 5 i) (7 + 5 i) = 7 (7) + 7 (5 i) - 5 i (7) - 5 i (5 i)$

Step 2 ：Simplify the result: $49 + 35 i - 35 i - 25 i^{2} = 49 - 25 (- 1)$

Step 3 ：Combine the real parts: $49 + 25 = 74$

Step 4 ： $74$