....................................

syarat = a > 3x 
f'(x) = 1 - 3/2va-3x = 0 
3/2 = va-3x 
1 = x + 3/2 
x = -1/2 
3/2 = va+3/2
9/4 = a+3/2 
a = 9/4-3/2 = 9-6/4 = 3/4 E