Divide 40 by 8 minutes to find the quantity per minute for one machine:
40 / 8 = 5 per minute.
One machine does 5 envelopes per minute.
Now divide 120 by 5 to find the number of machines needed:
120 / 5 = 24
24 machines would be needed.
X + (7 - 3i) + (5 + 9i) + 13i = 10 - 5i
Subtract 13i from both sides
x + (7 -3i) + (5 + 9i) = 10 - 18i
Subtract (5 + 9i). MAKE SURE YOU SUBTRACT 9i TOO. In other words, distribute the negative and subtract 5 and 9i at the same time.
x + (7 - 3i) = 5 - 27i
Do the same with (7 - 3i). You'll be adding 3i since -(-3i) = 3i.
x = -2 - 24i
C is answer no explanation needed
