Question 1004435
-x^2+10x+17=f(x)
vertex x value is -b/2a, which is -(-10/2)=5
f(5)=-25+50-17=8
vertex is at (5,8)
Symmetrical around x=5
Next step is y-intercept when x=0 and that is at (0,-17)
Because of symmetry, the change in x from 5 to 0 causes y to change from 8 to -17
That means from -5 to -10, going the other way, the y-value is the same, -17.
There are now 3 points, the vertex, and (0,-17) and (-10,-17).  One can put in 1,2 or other values for x, but these are enough to graph it.
Domain is all x values.
Range are all y values less than or equal to  8, which is at the vertex.
{{{graph(300,300,-10,15,-20,20,-x^2+10x-17)}}}