I have a few more questions that I'm not understanding. Its multiple choice however I would appreciate a breakdown on how to solve.

1.Evaluate without a calculator, using the order of operations. -2^2+20-|8-20|-squareroot of 64

a. -36
b. 4
c. 28
d. -4

2.Simplify the expression. Square root of -16

a. 4
b. -4
c. -8
d. Not a real number

2 answers

-2^2+20-|8-20|-squareroot of 64
= -4 + 20 - 12 - 8
= -4

√-16 ----> not a real number

( in your first one, notice the difference between
-2^2 and (-2)^2 )
-2^2+20-|8-20|-√64
-4+20-|-12|-8
-4+20-12-8
-4
(D)

since x^2 >= 0 for all real x,
(D)
√-16 = 4i, a complex number