Question 136441
You now have two equations and three unknowns. You can't solve that for specific values of x and y. You CAN find the graph. With the graph, you can easily find values for x and y once you are given some additional information.

Given:{{{A=xy}}} and {{{x = (500 - 2y)/10}}}
{{{A = ((500-2y)*y)/10}}}
{{{10A = 500y - 2y^2}}}
{{{5A = 100y - y^2}}}
{{{A = 20y - (y^2)/5}}}


Let's assume the person wants to get the maximum area

Plot the parabola to find the max value of A OR use derivatives to find the f` OR set A equal to 0 and find the two y values that are solutions. Then use that to find the line of symmetry and get the vertex.