Rant paid $12 for 4 baseball card packs . how many baseball card packs can he purchase for $21?

An architect is designing a water fountain for a park she uses the given function to model the water jet flowing from the fountain nozzles where h(x) gives the height of the water jugs in feet x feet from the starting point h(x)=-1/20x+x+15

Solve the equation below: (x+4)/6x=1/x a. x=2 b. x=0,2 c. x=-2 d. x=0,-2

Determine which expressions represent real numbers and which expressions represent complex number. asaaap! plis!