math
posted by chip .
whats the vertex of 4y^2+4y16x+13=0?

rearrange, then complete the square ....
16x = 4y^2 + 4y + 13
4x = y^2 + y + 1/4  1/4 + 13/4
4x = (y + 1/2)^2 1/4 + 13/4
4x = (y+1/2)^2  3
x = (1/4)(y + 1/2)^2  3/4
can you read the vertex from that? 
so is it (3/4,1/2)?

yes, good for you to notice that you had to read the x and y in inverse form.