Help?

1)
3i-10/8i-5

2)
11i^2+1/-12i-8

4 answers

I assume you are meant to express #1 as a complex number in standard form: a+bi

to do that, it helps to express the given values in standard form:
(-10+3i)/(-5+8i)
Now, multiply top and bottom by -5-8i, because

(a+bi)(a-bi) = a^2 + b^2

(-10+3i)(-5-8i) = 50 + 80i - 15i - 24i^2 = 50 + 65i + 24 = 74+65i

(-5+8i)(-5-8i) = 25 + 84 = 109

So, the fraction is

74/109 + 65/1209 i

For #2, 11i^2 = -11, so it is just -10/(-8-12i)
= -10(-8+12i)/208
= (80 - 120i)/208
Thank YOU Very Much.
Help Please?

1.30√-25 x 8√-49

2. 6√-64 + 12√-36

3. 4√-13 - 6√-13
30√-25 x 8√-49 = 30*5i * 8*7i = 8400i^2 = -8400

6√-64 + 12√-36 = 6*8i + 12*6i = 120i

4√-13 - 6√-13 = (4-6)√-13 = -2√13 i