If productCost and productPrice are numeric variables, and productName is a string variable, which of the following statements are valid assignments? If a statement is not valid, explain why not.
productCost = 100
productPrice = productCost
productPrice = productName
productPrice = "24.95"
15.67 = productCost
productCost = $1,345.52
productCost = productPrice - 10
productName = "mouse pad"
productCost + 20 = productPrice
productName = "3-inch nails"
productName = 43
productName = "44"
"99" = productName
productName = "brush"
battery = productName
productPrice = productPrice
productName = productCost