--------------------------------------------------------------------- Define x : --------------------------------------------------------------------- Let the cost of the toy train be x. Toy Train = x Toy car = 2x - 20
--------------------------------------------------------------------- Construct equation : --------------------------------------------------------------------- The toy car costs $100. ⇒ 2x - 20 = 100
--------------------------------------------------------------------- Find the cost of the toy train : --------------------------------------------------------------------- Cost of the toy train = x = $60
--------------------------------------------------------------------- Answer: The toy train costs $60. ---------------------------------------------------------------------
I'm not sure what operation you're using but for example, subtraction and addition are inverse operations and division and multiplication are inverse operations
