I will assume you meant y=-10(x^2)+20x-15
In which case to find the vertex you would do -b/2a
So for this one that would be -20/-20 which is just 1, that is the x value of the vertex so to find the y value you plug 1 into the equation and get 5 so the
Vertex is (1,5)
Since the a value is negative the equation will have a max value and that value will be the same as the y value of the vertex.
Max value: y=5
Axis of symmetry is the x value of the vertex
Axis of symmetry: x=1
The range is all possible y values so in this case it is from the y value of the vertex and down
Range: {y|y<5}
Domain is all possible x values which is all real numbers for every quadratic.
In summary:
Vertex is (1,5)
Axis of symmetry: x=1
Max value: y=5
Range: {y|y<5}
Domain: all real numbers
