Which two expressions are equivalent to 20r+60t? (Pick two choices) *
4(5r+15t)
5(5r+12)
60(20r+t)
20(r+3t)

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?