Question

Write the quadratic function (or one possible quadratic function ) in vertex form or standard form, from the following information:

zeros at (0,0) and (7,0), and opening down


I know the answer is
-x(x-7)=-x^2+7x

but I don't get it

please baby talk
thank you and sorry

Answer 1

the zeroes mean that
y = a(x)(x-7)
since it opens downward, a must be negative
so, a = -1 is the simplest choice

Answer 2

Oobleck, but how do I know how to write it,
Vertex form is a(x-h)^2+k

and standard form is:
ax^2+bx+c
so how does the zeros at (0,0) and (7,0), and opening down
end up like this as the answer:
-x(x-7)=-x^2+7x


sorry, I am really bad at this