Gabriela is building a brick wall. Each row of bricks is 6.5\,\text{cm}6.5cm6, point, 5, start text, c, m, end text tall except that the top row is 1\,\text{cm}1cm1, start text, c, m, end text shorter because it has no mortar. She wants the wall to be 259\,\text{cm}259cm259, start text, c, m, end text tall. Which equation can we use to determine rrr, the number of rows of bricks Gabriela needs in her wall?