What is the solution of the system? Use substitution.
y=-3x
x + y = -4

A. (-2,-6)

B. (2, -6)
c. (2,6)

D. (-2, 6)

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?