Answer :
Given:
[tex]f(x)=-5x+6[/tex]We need to find f(3a-5)
So, substitute with x = 3a - 5 into the given function
So,
[tex]\begin{gathered} f(3a-5)=-5\cdot(3a-5)+6 \\ f(3a-5)=-5\cdot3a-5\cdot-5+6 \\ f(3a-5)=-15a+25+6 \\ \\ f(3a-5)=-15a+31 \end{gathered}[/tex]so, the answer will be: f(3a-5) = -15a + 31