Question

I am trying to do my math homework, but I have never used Delta before and I don't understand how to use it properly.

Answer 1

Δ is a letter just like any other letter, for the sake of simplification is no any different than a or b or z, just a Greek letter, as opposed to a Latin letter, anyhow,

$\bf Q=mC\Delta T\implies \cfrac{Q}{m\Delta T}=C$