Tom starts lawn mowing business before he can begin he purchases a new lawnmower each weekend he mows the same number of lawns and earns the same amount of money write and equation to show how much money he's earned any week

To be able to give the answer to this item, we are to represent first with any variables the amount he earns each weekend for mowing the same field. Also, we represent the number of weeks he had worked by the variable y. The total amount of money he will have after working for y weeks is,
 
                           T = xy

Since, we are not given with any other information of the other expenses that have to be paid  then we can say that if T is already equal to the price of the new lawnmower then, Tom will be able to purchase it and begin his lawn mowing business in due time. 

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