Answer:
option (4)
Step-by-step explanation:
The general form of a quadratic function is given by :
[tex]f (x) = ax^ 2 + bx + c[/tex]
Where a,b and c are real numbers and a is nonzero.
Option (1)
[tex]f (x) = 3x^ 2 + 12x + 5[/tex]
It is a quadratic function. Here, a = 3, b = 12 and c = 5
Option (2),
[tex]f (x) = x^ 2 + x + 1[/tex]
It is a quadratic function where a = 1, b = 1 and c =1
Option (3),
[tex]f(x)=5x^ 2 + 8x[/tex]
It can also be written as :
[tex]f(x)=5x^ 2 + 8x+0[/tex]
It is a quadratic function where a = 5, b = 8 and c = 0
Option (4),
It can also be written as :
f(x) = 5x + 3
It is a linear function. It is not a quadratic function.
Hence, option (4) is the correct option. It is not a quadratic function.
