How many operations does it take to solve 4/5x=20

Brook states that the distance on the line is 4 units. caleb states that the whole line does not have a distance because it continues on forever. vivian states that the line is 6 units long. which distance did brook measure? which distance did vivian measure?

7x+8y=-18, 4x-9y=-3 solve the system of equations

The volume of a sphere is increased by 6%. calculate the corresponding percentage increased in it area.