I'm getting really frustrated with this. me -9c-12+3c=12 c=?

Which of these choices show a pair of equivalent expressions?

The volume of a cone is 37x3 cubic units and its height is x units. which expression represents the radius of the cone's base, in units? 1 s o 3x o 6x obx 93x2

Answer asap ill give ! ’ a sample of radioactive material decays over time. the number of grams, y , of the material remaining x days after the sample is discovered is given by the equation y = 10(0.5)^x. what does the number 10 represents in the equation? a. the half-life of the radioactive material, in days b. the amount of the sample, in grams, that decays each day c. the time, in days, it will take for the samples to decay completely d. the size of the sample, in grams, at the time the material was discovered