PLEASE HELP ME!! Quick geometry again!

Subtract 8 1/6 - 4 5/6 . simplify the answer and write as a mixed number.

Mr. walker gave his class the function f(x) = (x + 3)(x + 5). four students made a claim about the function. each student’s claim is below. jeremiah: the y-intercept is at (15, 0). lindsay: the x-intercepts are at (–3, 0) and (5, 0). stephen: the vertex is at (–4, –1). alexis: the midpoint between the x-intercepts is at (4, 0). which student’s claim about the function is correct?

What could explain what happened when the time was equal to 120 minutes