What are the foci of the ellipse given by the equation 100x^2+25y^2=2500

Simple:What are the foci of the ellipse given by the equation 
100x^2+64y^2=64,000
x^2/640+y^2/1000=1
This is an equation of an ellipse with vertical major axis.
Its standard form: , a>b, (h,k)=(x,y) coordinates of center

center:(0,0)
a^2=1000
b^2=640
c^2=a^2-b^2=1000-640=360
c=√360≈18.97
Foci: (0, 0±c)=(0,0±18.97)=(0,-18.97) and (0,18.97) does this help

First subtract 10 from both side
y^2+6y-16=0
(y+8)(y-2)=0
-8 and 2