Remove the brackets
6 - t + 7 - t - 4 + t = 0
Eliminate the two opposite t because they cancel out to each other
6 + 7 - t - 4 = 0
Add and subtract
6 + 7 - 4 = 9
Thus:
9 - t = 0
Bring the 9 over to the 0 to isolate the -t
-t = 0 - 9
Calculate:
-t = -9
To get rid of the negative on the variable we have to divide it by -1 to make it positive bc negative divided by negative equals positive. Since we are dividing -1 to the -t we also have to divide -9 by -1.
t = 9