[9.06] Create your own quadratic equation whose graph opens down and crosses the x-axis at two points. Use graphing technology to graph the parabola and approximate the coordinates of the vertex and x-intercepts. Provide your quadratic equation, the coordinates of the vertex, and the x-intercepts. Using complete sentences, explain the process of graphing the parabola using graphing technology and why using graphing technology is beneficial.

Question

anonymous · Answer

Anybody reading this? :/

anonymous · Answer

have to open down or doesn't matter ?

anonymous · Answer

Must open down.

anonymous · Answer

$$y=-x ^{2}-10x-21$$
vertex= -b/2a
 -(-10)/2(-1)=-5
substitution x=-5 find y
$$y=-(-5)^{2}-10(-5)-21$$$$y=-25+50-21$$
y=4
vertex= ( -5.4)
set y=0 find x intercept
$$-x ^{2}-10x-21 = 0$$(x+7)(x+3)=0
x=-7
x=-3