So we have to figure out when 12x squared minus 200x plus 600 is equal to zero. What x values gets my derivative to be equal to zero? When is my slope equal to zero? I could also look for critical points where the derivative is undefined, but this derivative is defined, especially throughout my domain of x that I care about, between zero and 10. So I could try to factor this or try to simplify this a little bit, but I'm just gonna cut to the chase and try to use the quadratic formula here. So this is the x's that satisfy this. It's going to be, x is going to be equal to, so negative b, so it's 200, negative negative 200 is positive 200, plus or minus the square root of b squared, which is negative 200 squared, so I could just write that as 200 squared.