To find 10 f(x) means multiply (-2x-5) by 10
[tex]\begin{gathered} 10f(x)=10(-2x-5) \\ 10f(x)=10(-2x)+10(-5) \\ 10f(x)=-20x-50 \end{gathered}[/tex]To find 5 g(x) multiply (5x+2) by 5
[tex]\begin{gathered} 5g(x)=5(5x+2) \\ 5g(x)=5(5x)+5(2) \\ 5g(x)=25x+10 \end{gathered}[/tex]Now let us find 10 f(x) - 5 g(x)
[tex]10f(x)-5g(x)=-20x-50-(25x+10)[/tex]Multiply the bracket (25x+10) by (-)
[tex]10f(x)-5g(x)=-20x-50-25x-10[/tex]Add the like terms
[tex]\begin{gathered} 10f(x)-5g(x)=(-20x-25x)+(-50-10) \\ 10f(x)-5g(x)=-45x+(-60) \\ 10f(x)-5g(x)=-45x-60 \end{gathered}[/tex]