# Advanced Algebra

posted by
**Aly**
.

I some problems that I need help with please.

Add or subtact as indicated and write the results in standard form.

4. 6-(-5+7i)-(7-2i)

Divide and express the result in standard form. --These problems I don't understand, do you have to multply the denominator by the numerator?

7. (6-3i)/(9+2i)

8. (3-3i)/ (5-3i)

Perform the indicated operations and write the result in standard form.

17. (-4 - square root of -36)^2 I got -20+48i

19. ( square root of -16)(square root of -4) This one I don't understand.

25. (-42 + square root of -180)/6 this one I don't understand.

6-(-5+7i)-(7-2i) =

6 + 5 - 7i - 7 + 2i =

4 - 5 i

(6-3i)/(9+2i) =

(6-3i)(9-2i)/[(9+2i)(9-2i)]

(9-2i)(9+2i) = 81 + 4 = 85

(6-3i)(9-2i) = 54 -6 - 12i - 27i =

48 - 39 i

(-4 - square root of -36)^2 =

(-4 - 6 i)^2 =

(4+6i)^2 =

16 - 36 + 48 i = -20 + 48 i

( square root of -16)(square root of -4) =

4 i * 2i = -8