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?
choose 1
choose 1

(choice a)
a
6.5(r-1)=2596.5(r−1)=2596, point, 5, left parenthesis, r, minus, 1, right parenthesis, equals, 259

(choice b)
b
6.5r-1=2596.5r−1=2596, point, 5, r, minus, 1, equals, 259

(choice c)
c
6.5r-r=2596.5r−r=2596, point, 5, r, minus, r, equals, 259

(choice d)
d
6.5(r-1)+1=2596.5(r−1)+1=2596, point, 5, left parenthesis, r, minus, 1, right parenthesis, plus, 1, equals, 259