Explanation:
[tex]since \to F = \frac{GMm}{ {r}^{2} } \\ b.... \: if \: the \: masses \: of \: both \: are \: doubled \\ then \to \: \boxed{F \: is \: doubled} \\ \\ c.... \: if \: their\:distance \: apart \: is \: doubled \\ then \to \: \boxed{F \: decrease s\: by \: double} \\ \\ d.... \: if \:distance \: between \: them \: is \: cut \: in \: half \: \\ then \to \: \boxed{F \: is \: doubled}[/tex]
