On a number line, a number, b, is located the same distance from 0 as another number, a, but in the opposite direction. The number b varies directly with the number a. For example b = 2 3/4 when a = –2 3/4. Which equation represents this direct variation between a and b?
b = –a
–b = –a
b – a = 0
b(–a) = 0