Question 150919
If {{{a>0}}}, then the graph will open upwards like this


{{{ drawing(500, 500, -10, 10, -10, 10,
 graph( 500, 500, -10, 10, -10, 10,2(x-3)^2+5)

)}}} Graph of {{{y=2(x-3)^2+5}}}. Notice how {{{a=2>0}}}



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If {{{a<0}}}, then the graph will open downwards like this


{{{ drawing(500, 500, -10, 10, -10, 10,
 graph( 500, 500, -10, 10, -10, 10,-3(x-6)^2-2)

)}}} Graph of {{{y=-3(x-6)^2-2}}}. Notice how {{{a=-3<0}}}