the correct question is
let f(x)=4x+3 and g(x)=-2x+5. find (fog) (5)
we have that
f(x)=4x+3
g(x)=-2x+5
(fog) (x)---------> f(g(x))------> 4*[-2x+5]+3---------> f(g(x))=-8x+20+3
f(g(x))=-8x+23
then
(fog) (5)=-8*5+23---------> (fog) (5)=-40+23
(fog) (5)=-17
the answer is (fog) (5)=-17