Plz, Help me! What is the equation of a circle with a radius of 5 and a center located at (7,9)?
a. (x - 9)^2 + (y - 7)^2 = 5
b. (x - 7)^2 + (y - 9)^2 = 5
c. (x - 7)^2 + (y - 9)^2 = 25
d. (x - 9)^2 + (y - 7)^2 = 25

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?