5x+15 - 2 = 2 - x+9
Given Or Equivalent Equations

Atorch and a battery cost 2.50 altogether. the torch costs 1.50 more than the battery. what fraction of the total price is the torch? give your answer in its simplest form.

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?

1) prove that 731^3−631^3 is divisible by 100 2) prove that 99^3−74^3 is divisible by 25