tolong d jawab y...

x^2 + 4x +a -4 =0
@ = 3β

@ + β = -b/a
3β+β = -4
4β = -4
β =-4/4 = -1

@ = 3β
@ = 3.-1 = -3

@.β = c/a
-3.-1 = (a-4)/1
3 = a-4
a = 3+4 = 7