Question

you answered this and I thank you:
"the zeroes mean that
y = a(x)(x-7)
since it opens downward, a must be negative
so, a = -1 is the simplest choice"

the question was: Write the quadratic function (or one possible quadratic function) in vertex or standard form, from the following information:
zeros at (0,0) and (7,0), and opening down.

so....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

Answer 1

If the roots are a and b, then (x-a)(x-b) = 0
Factor Theorem or Remainder Theorem

-x^2+7x
-(x^2-7x)
-(x^2 - 7x + (7/2)^2) + (7/2)^2
-(x - 7/2) + 49/4

Answer 2

no comprendo...thank you anyway