Emanuel has 745 pictures in his phone. his memory is getting full so he starts deleting 20 pic per day. define each variable and write an algebraic expression to describe any given number of pictures remaining on his phone any given day

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