Evaluate the expression ( 1 + 2 i ) ( − 2 − 1 i ) and write the result in the form a + b i .
1 answer:
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Answer:
D
Step-by-step explanation:
Say the short leg is x and the hypotenuse is y. Then, y = 3x (because "The length of the hypotenuse of a right triangle is three times the length of the shorter leg.")
Use the Pythagorean Theorem: a^2 + b^2 = c^2 (where a and b are the legs and c is the hypotenuse). Here, we can say a = x and b = 12 and c = y. So:
x^2 + 12^2 = y^2
x^2 + 144 = (3x)^2
x^2 + 144 = 9x^2
8x^2 = 144
x^2 = 18
x =
The answer is D.
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