Don't go by my answers pls

19)  ( )^2 =

20) - = -81

21)   = 16

Step-by-step explanation:

The only wrong ones are

19)  ( )^2 =

20) - = -81 ... negative is not inside a parenthesis that's why it is still negative

21) you can add another way is = 16

Everything else looks good.  Great job!

180

step-by-step explanation:

12-2=10

20-2=18

18x10=180

the answer is b.

step-by-step explanation:

identity property is where 0+whatever number=whatever number. basically 0+ a number.