The like terms are ones that have the same variable in them, or that dont have a variable at all attached. One pair of like terms is t and -2t, which combine to t+(-2t) = t-2t = -t
The other pair of like terms are 4 and 3 which add to 7
So t+4+3-2t simplifies fully to -t+7, which is the same as 7+(-t) = 7-t
We cannot simplify any further from here as the 7 and -t are not like terms.
