What is the gravitational strength "G"?

[LCSphysicist]

Homework Statement

Gravitational topic

Relevant Equations

G = -Gm/r^3

I am doing a book that have only exercises, and an introduction to the posterior theme, so, in the introduction, there is the relevant equations, and there is a equation: G = -Gm/r^3 called strength G, in the gravitational topic, what is this? I never saw it.

 

[haruspex]

Homework Statement:: Gravitational topic
Relevant Equations:: G = -Gm/r^3

I am doing a book that have only exercises, and an introduction to the posterior theme, so, in the introduction, there is the relevant equations, and there is a equation: G = -Gm/r^3 called strength G, in the gravitational topic, what is this? I never saw it.

It looks close to $\vec g=-Gm\frac{\vec r}{r^3}$, which does make sense,