Question 879813
determine which of the following statements are true if parabola 1 has the equation y= x^2-4x-12 and parabola 2 has zeros at x=4 and x=-2? 
does parabola 1 has a lower minimum then parabola 2? yes
does parabola 1 crosses the y-axis higher then parabola 2? no
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parabola 1:
y= x^2-4x-12 
complete the square:
y=(x^2-4x+4)-4-12
y=(x-2)^2-16
vertex: (2,-16)
minimum at -16
y-intercept:
set x=0
y=-12
..
parabola 2:
zeros at x=4 and x=-2
(x-4)(x+2)=x^2-2x-8
complete the square:
y=(x^2-2x+1)-1-8
y=(x-1)^2-9
vertex: (1,-9)
minimum at -9
y-intercept:
set x=0
y=-8
..
see graph below as a visual check on the answers:
parabola 1:red curve
parabola 2:green curve
{{{ graph( 300, 300, -10, 10, -20, 10, x^2-4x-12,x^2-2x-8) }}}