Answer :
To translate vertically a function we make the transformation:
[tex]f(x)+c[/tex]where c is the number of units we want it to move. If c is positive then we move the function up, whereas if c is negative we move the function down.
Then in this case we have that c=-8, then the function g would be:
[tex]\begin{gathered} g(x)=(2x+5)-8 \\ g(x)=2x-3 \end{gathered}[/tex]Therefore:
[tex]g(x)=2x-3[/tex]