Answer:
1.) 6
2.) -1
3.) 36
4.) 1/3
5.) 90
Step-by-step explanation:
1.) -12/a
-12/a -> -12/2
=6
2.) a+ (-b)
a+(-b) -> 2+(-3)
=-1
3.) 3a (12-2b)
3a(12-2b) -> 3(2) (12-2x3)
6(12-6)
6(6)
=36
4.) 2a-c/b
2a-c/b -> 2(2)-5/3
4-5/3
=1/3
5.) 3abc
3abc-> 3x2x3x5
=90
8(5) - 4y = 39
40 - 4y = 39
-4y = -1, y = 1/4
Solution: y = 1/4
There are two ways to work this out: normal variables or using "imaginary" numbers.
Normal variables:
![(7+2i)(3-i)\\(7*3)+[7*(-i)]+(3*2i)+[2i*(-i)]\\21-7i+6i-2i^{2}\\\\21-i-2i^{2}](https://tex.z-dn.net/?f=%20%287%2B2i%29%283-i%29%5C%5C%287%2A3%29%2B%5B7%2A%28-i%29%5D%2B%283%2A2i%29%2B%5B2i%2A%28-i%29%5D%5C%5C21-7i%2B6i-2i%5E%7B2%7D%5C%5C%5C%5C21-i-2i%5E%7B2%7D)
Imaginary numbers:
Using the result from earlier:

Now since

, then the expression becomes:
Your answer would be (w+2)(w−10). If you want me to explain please don't hesitate to ask.
yes it is .....,...............reflex angle