Can anyone please teach me or send me the answer if thus​

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

The difference of three and the reciprocal of a number is equal to the quotient of 20 and the number. find the number.

Arectangle plot measure 20ft. by 30ft. a 3-ft.-wide sidewalk surrounds it.find the area of the sidewalk.