Ruby bought 15 cell phone cases for a total of $145.80. she sells them for $19.50 each, but she is only able to sell 5 of them.
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Answer:
Step-by-step explanation:
Combine real terms and combine complex terms
1) 3 + 2i + 2 - 5i = 3 +2 + 2i - 5i
= 5 + (2-5)i
= 5 + (-3)i
= 5 - 3i
3) 2 - (1 - 2i) + (4 -5i ) - (1 - 3i) = 2 -1 + 2i + 4 - 5i - 1 + 3i
{- is distributed to (1 - 2i) & - is distributed to (1- 3i)}
= 2 - 1 + 4 + 1 + 2i - 5i + 3i
= 6 +0i = 6
5) 4 - 3i + 4 + 3i = 4 +4 -3i + 3i
= 8
7) (3 - 2i)² + (3 +2i) = 3² - 2*3*2i + (2i)² + 3 + 2i {(a - b)² = a² - 2ab +b²}
= 9 -12i + 4i² + 3 + 2i
= 9 - 12i + 4*(-1) + 3 + 2i {i² = -1}
= 9 +3 - 4 - 12i +2i
= 8 - 10i