#11 HELP PLZZZZZZZZZZZZZZZZ

Mathematics

2 answers:

Lelu [443]3 years ago

6 0

(a + 4i)(9 - bi) Substitute a = 6
(6 + 4i)(9 - bi) Remove the brackets with a foil.
54 - 6*bi + 36i - 4bi^2 Simplify
54 - 6bi +36i + 4b

The only way this can be a real number is if the is disappear. so
-6bi + 36i = 0
-6bi = - 36i Divide by -6i
b = 6

C <<<< answer

ArbitrLikvidat [17]3 years ago

4 0

I wanna say B=4 im like 99% sure

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Answer:

Option B - $=8.4672\times 10^{13}$

Step-by-step explanation:

Given : Astronomers measure large distances in light-years. One light-year is the distance that light can travel in one year, or approximately 5,880,000,000,000 miles.Suppose a star is 14.4 light years from earth.

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Solution :

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In scientific notation, $5.88\times 10^{12}$ miles.