To calculate minimum value, do -b/2a to get the x-value, and plug it in to get the y-value:
-6/8 = -3/4
[tex]4 * (-\frac{3}{4} )^{2} + 6 (-\frac{3}{4} ) - 18 = \frac{9}{4} - \frac{9}{2} - 18 = - \frac{81}{4} [/tex]
So the minimum value of g(x) is -81/4
This shows that g(x) has a lesser minimum value than f(x)