What is a logic mathematical argument

What is the factored form of the following expressions? d^2 – 13d + 36

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

Macy spent $36 on jeans. this was $12 less than twice what she spent on a shirt. which equation to solve this, 12x=36 2x=36-12 2x-12=36 12-2x=36