1. ## need help! problem solving involving quadratic equations

Ok, here's the question....

A lifeguard uses 700 m of marker buoys to rope off a rectangular swimming area in a lake. One side of the swimming area is a sandy beach.

a) Determine the dimensions that will result in the maximum swimming area.
b) What is the maximum swimming area?

2. $\displaystyle 2a+b=700$. $\displaystyle A=ab=a\cdot\left(700-2a\right)$ It's roots are: $\displaystyle 0\text{ and } 350$ therefore its maximum is at $\displaystyle a=175$. So the answer: swimming area 175 x 350 which is $\displaystyle 61250\text{ }\rm{m^2}$.