the correct answer is -9
The axis of symmetry for the graph of the function f(x) = 3x2 + bx + 4 is x = . What is the value of b?
⇒ -9
i just took the test
Answer:
b =-9
Step-by-step explanation:
Given is an equation of a parabola
[tex]f(x) = 3x^{2} +bx+4[/tex]
This is a parabola open up
Axis of symmetry is given as x = 3/2
Hence parabola would have equation of the form
[tex]f(x) = a(x-\frac{3}{2} )^2+k[/tex]
[tex]f(x) = ax^2-2ax(\frac{3}{2} )+\frac{9a}{4} +k[/tex]
Compare this with the given equation
Equate the coefficient of x square to get
a =3
Equate coefficient of x to get
-3a = b
Or b=-3(3) = -9
Hence value of b =-9
