A bridge on a river is modeled by the equation h = -0.2d2 + 2.25d, where h is the height and d is the horizontal distance. For cleaning and maintenance purposes a worker wants to tie a taut rope on two ends of the bridge so that he can slide on the rope. The rope is at an angle defined by the equation
-d + 6h = 21.77. If the rope is attached to the bridge at points A and B, such that point B is at a higher level than point A, at what distance from the ground level is point A?

A. 2.21 units
B. 4 units
C. 5 units
D. 8.21 units

Help. pl!

Question

A bridge on a river is modeled by the equation h = -0.2d2 + 2.25d, where h is the height and d is the horizontal distance. For cleaning and maintenance purposes a worker wants to tie a taut rope on two ends of the bridge so that he can slide on the rope. The rope is at an angle defined by the equation
-d + 6h = 21.77. If the rope is attached to the bridge at points A and B, such that point B is at a higher level than point A, at what distance from the ground level is point A?

A. 2.21 units
B. 4 units
C. 5 units
D. 8.21 units

Help. pl!

zepdrix · Answer

Hmm I'm having trouble visualizing the maintenance guy...
let's draw this out, maybe we can figure it out.

zepdrix · Answer

|dw:1404074069952:dw|For our bridge function, the height is modeled by a parabola opening downward. See how the leading term is a square and is negative?