Leo planted 912 pine trees in equal rows. The number of trees in each row was 29 more than the number of rows. How many rows of pine trees did Leo plant?

Let x be the number of rows.

Leo plants x+29 trees in each row. Hence the number of rows is given by

912 x

------ =

x+29

i.e., after simple algebraic manipulations, 912= x^2 +29x or

x^2 +29x - 912= 0

Solving this second-degree equation, gives two solutions: x=-48, and x =19. We can keep only the positive solution since the number of rows cannot be a negative number.

So the number of rows Leo planted is x=19