What is the difference between |-3| and -3

Cara earns a base pay of $1800 per month at a car dealership plus a commission of 6% of her sales. what are caras total earning in a month in which she sells $40000 worth of merchandise

The center of the circumscribed circle lies on line segment and the longest side of the triangle is equal to the of the circle.

What is the radius of a circle with an area of 78.5 cubic inches? use 3.14 for pie