What is the y value of the vertex of 4^2+8x-8

When lulu enlarged her drawing of a rabbit, the enlarged picture appeared to be distorted. which statement about the transformation applied to her drawing is true?

[10 points, algebra 2-simplifying complex fractions]according to my answer key the restrictions are -1 and 4. but why not positive 1?

X^2/100+y^2/25=1 the length of the major axis is: a)5 b)10 c)20