Solution:
Given the functions below
[tex]f\mleft(x\mright)=19x\text{ }and\text{ }g\left(x\right)=-3x-4[/tex]To find the composite function (fg)(x),
[tex](fg)(x)=(19x)(-3x-4)[/tex]Expand the brackets
[tex](fg)(x)=-57x^2-76x[/tex]Hence, the answer is
[tex]-57x^2-76x[/tex]