what is the equation to show the mass of a given object?

Question

in the equation f=m x a and a=f/m does m=a/f?

Answer 1

if F=ma, then to put m on its own, divide both sides by a:
F=ma
F/a = (ma)/a
m=f/a

You could also imigaine it as a triangle,

f
m a

That way you can easily see the equation to use just by covering the unknown.

Answer 2

m=f/a