Multiply 3i(−1 + 2i). What is the simplified version written in standard form, a + bi, where a and b are real numbers?

1 answer:

4 0

3i (- 1 + 2i) Remove the brackets.
3i (-1) + (2i)(3i) Look at the first set of brackets around the -1
-3i + 6i^2 But i^2 = - 1[ I hope that's the way you are using it]
-3i - 6 or -6 - 3i or -3(2 - i) <<<<< answer

You might be interested in

Some people think it is unlucky if the 13th day of a month falls on a Friday. Show that in every calendar year (non leap or leap

MakcuM [25]

We will set a variable, d, to represent the day of the week that January starts on. For instance, if it started on Monday, d + 1 would be Tuesday, d + 2 would be Wednesday, etc. up to d + 6 to represent the last day of the week (in our example, Sunday). The next week would start over at d, and the month would continue. For non-leap years:
If January starts on d, February will start 31 days later. Following our pattern above, this will put it at d + 3 (28 days would be back at d; 29 would be d+1, 30 would be d+2, and 31 is at d+3). In a non-leap year, February has 28 days, so March will start at d+3 also. April will start 31 days after that, so that puts us at d+3+3=d+6. May starts 30 days after that, so d+6+2=d+8. However, since we only have 7 days in the week, this is actually back to d+1. June starts 31 days after that, so d+1+3=d+4. July starts 30 days after that, so d+4+2=d+6. August starts 31 days after that, so d+6+3=d+9, but again, we only have 7 days in our week, so this is d+2. September starts 31 days after that, so d+2+3=d+5. October starts 30 days after that, so d+5+2=d+7, which is just d. November starts 31 days after that, so d+3. December starts 30 days after that, so d+5. Remember that each one of these expressions represents a day of the week. Going back through the list (in numerical order, and listing duplicates), we have d, d, d+1, d+2, d+3, d+3, d+3, d+4, d+5, d+5, d+6 and d+6. This means we have every day of the week covered, therefore there is a Friday the 13th at least once a year (if every day of the week can begin a month, then every day of the week can happy for any number in the month).
For leap years, every month after February would change, so we have (in the order of the months) d, d+3, d+4, d, d+2, d+5, d, d+3, d+6, d+1, d+4, and d+6. We still have every day of the week represented, so there is a Friday the 13th at least once. Additionally, none of the days of the week appear more than 3 times, so there is never a year with more than 3 Friday the 13ths.

5 0

3 years ago

If the radius of a circle is 4 1/4 feet, what is the diameter

iragen [17]

All i know is that if the radius of a circle is 4 feet, the the diameter is 8 feet. Sorry, I don't know the rest.

4 0

2 years ago

What would x equal( rounded to the nearest tenth)

masya89 [10]

You are given the opposite: 16 km
You need to find x (adjacent)
The angle measure: 28 degrees
With opposite and adjacent, use tangent
Tan(28) = 0.5317094317
Tan(28) = 16/x
x = 16/0.5317094317
x = 30.0916
Round to nearest tenth
Solution: x = 30.1 km

5 0

2 years ago

Read 2 more answers

Hurry Please! :)

Sladkaya [172]

Area = b*h and in some cases * 2 so you need to do this, 64*52 + 40*28= 4448 yd2

8 0

3 years ago

Read 2 more answers

What is the value of

deff fn [24]

the answer is 2. see attached for step-by-step instructions. hope that helps!