Plz help.

Which expression gives you the distance between the points (5,1)and(9,-6)

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

Idon't get undoing if its pass adding and subtracting so can someone ? x-2 over 5 = 18