Answer: B ( - 9 )
Step-by-step explanation: given the function f(x) = 3x^2 + bx + 4
And the axis of symmetry x = 3/2
The formula to calculate the axis of symmetry is :
X = -b/2a
Where
X = 3/2
a = 3
Substitute X and a into the formula
3/2 = -b/ ( 2×3)
3/2 = -b/6
Cross multiply
-2b = 18
b = - 18/2
b = - 9
Therefore, the value of b is -9