What is the length of ab

Average acceleration: i have no idea how to do this.

The area of a rectangle is 10 cm^2. one side of the rectangle is x cm. express the perimeter of the rectangle in terms of x and show that this rectangle cannot have a perimeter of 12 cm. the perimeter of the rectangle in terms of x is __ cm

What is 100,000 times 1/100,000, using the standard method of multiplication? write the answer as 10 to a power.