You can differentiate both equation and find the value of x. First equation Dy/dx=-12x^3 The minimum value can be found by dy/dx=0 So -12x^3=0 X=0 Substitute this value on the equation and the result is the value wanted F(0)=0-14 F(0)=-14
Second equation Dy/dx=-3x^2
Equal 0 -3x^2=0 X=0
Substitute on the equation G(0)=0+2 G(0)=2 G(x)>f(x)