Answer:
A. 
Step-by-step explanation:

I am joyous to assist you anytime.
The possibility is 3 : 1/2 * 6/1 = 3/1
1/2 of 20 is 20/2 which is 10.
All you really need to do here is to divide 20 by 2 to get 10.
We substitute the given into the equation
given: a=-1, b=2, c=

=(

-1
=

-1
=

-1
=

-1
to continue, we can either find a common denominator or change the fraction to decimal.
Fraction to Decimal:

=-2.5
Equation=-2.5-1=-3.5
OR Common Denominator:
=


×

(denominator should be -2=common)
=

+

=

which also = to -3.5
-13is negative and is 13 spaces away from 0. 15 is positive and is 15 spaces away from 0.