Question 7495
*[invoke quadratic "x", 1, -8, 22]

the vertex is at the midpoint between roots (never mind that roots are complex, you can still add them and divide sum by half and get a real number). That midpoint is x=4. Calculate the value of x^2-8x+22 for x=4, and you would get the x and y value this way. 

*[invoke substitution "x^2-8x+22", "x", 4]

Answer: x=4, y=6