Sean has a bag containing x green marbles and two bags containing y blue marbles. he adds 15 marbles to the bag of green marbles and adds 6 marbles to each bag of blue marbles. the total number of marbles in all three bags is given by the expression (x + 15) + 2(y + 6). identify an equivalent expression.

Ascientist has 50 grams of a radioactive element. the amount of radioactive element remaining after t days can be determined using the equation (1) after two days the scientist receives a second shipment of 50 grams of the same element. the equation used to represent the amount of shipment 2 remaining after t days is 10) - 50 which of the following is an equivalent form of the expression for the amount remaining in shipment 2? what’s the answer?