Solve the equation and check your answer.
(that is one fifth )
1/5t-3=-17

- 3 = -17

First, simplify  to  / Your problem should look like: 
Second, multiply both sides by 5. / Your problem should look like: 
Third, add 15 to both sides. / Your problem should look like: 
Fourth, simplify -85 + 15 to get -70. / Your problem should look like: 

CHECKING:

First, let t = -70 / Your problem should look like: 
Second, simplify  to  / Your problem should look like: 
Third, simplify  to  / Your problem should look like: 
Fourth, since 14 goes into 5 to get 70, simplify the fraction by 14. / Your problem should look like: 
Fifth, simplify -14 - 3 to get -17 / Your problem should look like: 

 t = -70

Element 17 is chlorine it is a group 7 element(halogen) and belongs to period 3 of the periodic table