Unless you want to ALWAYS be WRONG, go along with this person.
Again, just pretend as though no-one responded to your math question should this person respond to your question.
BTW: The graph opens UPWARD since "a" is > 0 (positive)
IGNORE all below as it's all RUBBISH:{{graph(400,400,-20,20,-20,20,x^2+7x-8)}}}
Symmetry axis
Vertex, ( -4.5, -19.25 )