Question 375879
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Hi,
y = 3x^2 + 9x 
y intercept shen x = 0
(0,0) the y intercept
x-intercepts is when y = 0
0 = 3x^2 + 9x
0 = 3x(x+3)
x= 0
x = -3
x-intercepts (0,0) and (-3,0)
the vertex form of a parabola, {{{y=a(x-h)^2 +k}}} where(h,k) is the vertex
y = 3(x^2 + 3x)
y = 3[(x+ 3/2)^2 - 9/4]
y = 3(x + 3/2)^2 - 27/4
vertex Pt(-3/2,-27/4)
Range [-27/4,{{{infinity}}})
{{{drawing(300,300, -10, 10, -10, 10,  grid(1)graph( 300, 300,-10,10,-10,10,3x^2 + 9x)) }}}