Hello,
Find the equation of the axis of symmetry is like find the maximum or minimum point of this function.

The equation of the axis of symmetry is then :   


Coordinates of vertex :   
 
 
        
        
        
Yes, this is a right triangle!
The ratio is identifiable as a 3:4:5 triangle, one of the ratios to tell if a triangle is a right triangle
        
             
        
        
        
Ok, so 11:9
11-9 = 2
which means that 124= 2:1
124/2 = 62
so 62:0
now 11 x 62= 682
9 x 62= 558
so the ratio is 682:558
now 682 + 558 = 1,240
There are 1,240 total students in the school. 682 boys and 558 girls
        
             
        
        
        
A quadratic's discriminant can either be more than zero, less than zero, or exactly zero. When the discriminant is less than zero, there are no real solutions and the graph won't cross the x-axis. When it's exactly zero, there will be a real double root and the graph is tangent to the x-axis. When it's more than zero, there will be two real solutions and two x-intercepts.
Our graph has two intercepts, so it needs a positive discriminant more than zero. Choice A's is negative - no.
Choice B's is zero - no.
Choice C's is positive -yes.
Thus, "C" is the possible discriminant for the given graph.