I too got a fourth-degree equation, too.
But there is a way around it . . .
[quote]A 10-m ladder is leaned against a box (1 x 1 x 1 m) placed against a wall.
But the ground is so slippery that the ladder falls over the box and leans against the wall.
How high up on the wall does the ladder reach?
10 * - - - *
* | 1 |
* 1| |1
* | |
* - - - - - - - * - - - *
From the large right triangle: . .
The two smaller right triangles are similar.
. . So we have: . .
Substitute  into : .
and we have: .
. . and we have the quadratic: .
Use the Quadratic Formula to solve for ,
. . then back-substitute and solve for