Verified Answer :

caylus

Hello,
y=3x²+bx+3/4+4
= 3(x²+2b/6*x+b²/36)+19/4-b²/12
=3(x+b/6)²+19/4-b²/12
==>-b/6=3/2==>b=-9


Answer:

The value of b is -9.

Step-by-step explanation:

We are given a equation as:

\(f(x)=\frac{3}{4}+3x^2+bx+4\)

\(f(x)=3x^2+bx+\frac{19}{4}\)

clearly the graph of this function will be a parabola.

for any quadratic equation of the type \(f(x)=ax^2+bx+c\)

the equation of axis of symmetry is given by:

\(x=\frac{-b}{2a}\)  , here a=3 and b=b

also we are given axis of symmetry as \(x=\frac{3}{2}\)

that means \(\frac{-b}{2\times3}=\frac{3}{2}\)

\(b=-9\)