Idon't get why i missed c i know why i missed the table can someone me with c

Acertain population of bacteria demonstrates exponential growth doubles in size every 4 days. how long will it take the population to triple in size?

The rumpart family is building a new room onto their house. the width of the new room will be 16 feet. the length of the room will be 4% greater than the width. write an expression to find the length of the new room. what will be the area of this new room?

If f(x)=-x^2+6x-1 and g(x)=3x^2-4x-1,find(f+g)(x)