Find the length of each side of a square when the perimeter is 64

Which equation results from adding the equations in this system? x+6y=9 and -x+2y=-15

Carl's candies has determined that a candy bar measuring 3 inches long has a z-score of +1 and a candy bar measuring 3.75 inches long has a z-score of +2. what is the standard deviation of the length of candy bars produced at carl's candies?

Fill in the missing exponents in each box and show how you found the answer. (4 points: 2 points for each correct answer with work shown) c. (9^4)^? =9^1 d.(5^? )^3=5^1 *question marks represent the boxes