Graphing the derivative with the function can illustrate how to find these turning points. The function is increasing exactly where the derivative is positive, and decreasing exactly where the derivative is negative. On the graph of the derivative find the x-value of the zero to the left of the origin.
We have 3 / (x-5) - x/5 We make the GCF and we have 15/[ 5(x-5) ] - x(x-5)/[ 5(x-5)] = [ 15 - x(x-5) ] [5(x-5)] = [ 15 - x^2 + 5x] / [ 5 (x-5) ] = [15 - x^2 + 5x]/[5x - 25] An answer to your question is (15-x^2+5x)/(5x-25)
