Can anyone please help me find the rule

What is the y intercept of f(x)=(1/2)^x?

The length of a rectangular piece of land is 92 yards more than three times its width. the perimeter is 760 yards. find its dimensions.

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