Third option
[tex] 6(3)-4+3^2 [/tex]
Step-by-step explanation:
[tex]f(x) = 4 - {x}^{2} \\ \red{ \bold{ f(3) = 4 - {3}^{2} }} \\ \\
g(x) = 6x \\ \purple{ \bold{ g(3) = 6( 3)}} \\ \\
(g - f)(3) = g(3) - f(3) \\ (g - f)(3) = 6( 3) - ( 4 - {3}^{2}) \\ \orange {\boxed {\bold {(g - f)(3) = 6( 3) - 4 + {3}^{2}}}} \\ [/tex]
