center at origin by symmetry
x^2/a^2 + y^2/b^2 = 1
given that b = 6 center to focus = 7
but 7^2 = a^2-b^2
49 = a^2 - 36
a^2 = 85
a = sqrt 85
so
x^2/85 + y^2/36 = 1
write an equation in standard form for the ellipse with foci (7,0) and (-7,0) and y intercepts 6 and -6
1 answer