My problem is : 13=-t+4 my answer is 9=-t but I am not sure if my - should be on the # 9 or on the varible.
A neg# added to a pos # is a pos #?
Nice job solving the equation so far!
In order to solve for the variable, you have one more step to go:
-t = 9 ; which is the same as (-1)(t) = 9
You can move the negative to the other side by dividing both sides by -1.
t = -9
You can always multiply both sides by -1, which will make the variable positive and the number negative. If they want you to solve for t, you want to express t by itself, without the negative sign, so multiply both sides by -1 and t=-9.