At what points on the curve y=(x^2)/(2x+5) is the tangent line horizontal?

Question

y'=[(2x)(2x+5)-(2)(x^2)]/(2x+5)^2
=[2x^2+10x]/(2x+5)^2

I plugged 0 into x, and got the coordinates (0,0). How do I get the other pair of coordinates?

Thanks in advance.

Answer 1

Just from looking at 2x^2+10x and that has to be zero - I'd try -5