The equation 12.5(x + 20) = 460 describes Steve's exercise plan for the next 12 ½weeks. He wants to bike 20 miles per week and run x miles per week for a total of 460 miles. How many miles, x, should Steve run each week to achieve his goal?

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