Question 79419
Y=-X^2-6X+40
solving algebraically we get
(x+10)(x-4) or
x+10=0
x=-10 answer
x-4=0
x=4 answer
or solving graphically we get: 
{{{ graph( 300, 300, -12, 10, -12, 60, y = -x^2 -6x +40 ) }}} (graph 300x300 pixels, x from -12 to 10, y from -12 to 60, y = -x^2 -6x +40).