Answer:
x=-3.5
reason:
first, add 3 to both sides
this makes the equation -1/2x=7
then, divide both sides by -1/2
this will give you x=-3.5
There are a few you can choose from:
Statistics and probability
Geometry
Proofs
Triangles
Circles
Numerical sequences
Number Theory
etc.
Answer:
6
Step-by-step explanation:
The circumference of a circle is 
, so
. We can use this because the area of a circle is
. Thus,
.