Question 1084246
18x^2 +21x - 400
x=(1/36)(-21+/- sqrt (441+28800); sqrt (29241)=171
roots are 150/36 and -192/36 or 4.167 and -5.33
(25/6)^2+(16/3)^2=45.81
625/36+256/9
=625/6+1024/36
=1649/36 (exact)

{{{graph(300,300,-20,20,-100,100,18x^2+21x-400)}}}