HELPP I DONT UNDERSTAND THIS

Carl wants to buy a television that cost $500 including taxes. to pay for television he will use a payment plan that requires him to make a down payment of $125 and then pay $70.50 each month for six months what is the percent increase from the original cast of the television to the cost of the television using a payment plan.

#12 find the value of x. #13 find the value of the variable.

This is so harddd! solve. 1 + 1 = solve 4 + 4 = solve 3 x 3