VARIATIONS

V=a(m +t) a is the variation constant.
m=b(t +V) b is the variation constant.
Substitute m into the first equation, V=a[b(t + V) + t]=a[bV + (1 +b)t]
therefore, V-abV= a(1+b)t
(1-ab)V=a(1+b)t
V=a(1+b)t/(1-ab) therefore, V varies directly as t.
Substitute the first equation into the second one, m=b[t+ a(m+t)],
m= bt+ abm + abt, therefore, (1-ab)m= b(1+a)t
m=b(1+a)t/(1-ab), therefore, m varies directly as t.