Question 698656
the standard form {{{y= -6x^2 + 48x + 9}}}

change it to vertex form using completing the square


*[invoke completing_the_square -6, 48, 9]


the vertex of the parabola is at ({{{4}}},{{{105}}})


here is better graph


{{{ graph( 600,600, -6, 10, -5, 120, -6x^2 + 48x + 9) }}}