Answer:
[tex]t=\dfrac{k-rs}{3m}[/tex]
Step-by-step explanation:
It's like solving any equation, except we have letters instead of numbers .
k = 3tm + rs {subtract rs from both sides}
k - rs = 3tm {divide both sides by (3m)}
[tex]\dfrac{k-rs}{3m}=t[/tex] {swap sides}
[tex]t=\dfrac{k-rs}{3m}[/tex] m≠0
{m must be ≠0 because you cannot divide by 0. There is no t for m=0}