Pre calculus ph of substance which has a hydronium ion concentration?

What is the value of the expression below? (81^2)^1/8

X+ y = 5 ; x - y =3 solve using linear combination

Zoey made 5 1/2 cups of trail mix for a camping trip. she wants to divide the trail mix into 3/4 cup servings. a. ten people are going on the trip. can zoey make enough 3/4 cup servings so that each person gets one serving? b. what size would the servings need to be for everyone to have a serving?