What is the equation of the line through (2, -4) and (0, 4)

Ijust need to see how to do this. so you don’t have to answer all of them just a step by step explanation of one.

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.

Suppose a laboratory has a 30 g sample of polonium-210. the half-life of polonium-210 is about 138 days how many half-lives of polonium-210 occur in 1104 days? how much polonium is in the sample 1104 days later? 9; 0.06 g 8; 0.12 g 8; 2,070 g