Question

Find the value of k in the function f(x)=a(x-h)^2 +k with a<0 has at least one zero.

Answer 1

help please

Answer 2

if a<0 this means the parabola is opening down
k refers to the vertical shift, if you shift the parabola down below x-axis then there will be no zeros
if you shift it up, it will cross x-axis 2 times, thus 2 zeros
if k=0 (no shift) the parabola is touching the x-axis , thus 1 zero

hope this helps