The 4 functions are:
[tex]f_1 (x) = 8x[/tex]
[tex]f_2(x)=3x[/tex]
[tex]f_3(x)=4x^2+3[/tex]
[tex]f_4(x)=1.5 x[/tex]
Let's keep in mind that for large values of x, a quadratic function grows faster than a linear function:
[tex]ax^2 \ \textgreater \ kx[/tex] for large values of x
In this problem, we can see that the only quadratic function is [tex]f_3(x)[/tex], while all the others are linear functions, so the function that grows faster for large values of x is
[tex]f_3(x) = 4x^2 +3 [/tex]
