Someone explain algebra the easiest way possible

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?

If x is 6, then 7x= a. 13 b. 42 c. 42x d. 76

The graph shows the distance kerri drives on a trip. what is kerri's speed . a. 25 b.75 c.60 d.50