Please answer if only correct

What expression is equivalent to 42x-56y

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 the 17th term in the arithmetic sequence in which a6 is 101 and a9 is 83