What is the amplitude, period, and phase shift of f(x) = -3 cos(4x + π) + 6?

The period of cos is 2π
so the period of cos(4x +  π) is 2π/4 =  π/2
cos(4x +  π) = -cos4x =>   -3 cos(4x + π) + 6 = 3cos4x + 6 
phase shift may be [-π/4,π/4]
sorry, i forgot: amplitudee   is [-3,3]

The amplitudes of those functions are given by the constant in front of sin or cos!  
for example 
f(x) has an amplitude of 2 
g(x) has an amplitude of 1/2 
now for the period the formula is 2pi/constant next of x 
so for first equation period is 2pi/pi = 2 
and for second equation period is 2pi/2= pii think so