What is the minimum value of a^2+6a-7?

The minumum value of   a    will be at   -b/2a    (this 'a' is the coefficient of a^2....1)

 

min val ue of a   =   -6/2 = -3   

 

sub this value of a into the equation to find the minumunm value of the function    f(a) =  -3^2 + 6(-3) - 7 = -16 is the min value of the fxn