Given the function
[tex]f(x)=-2(x+5)[/tex]You need to calculate f(5), this is, to calculate the value of the function when x=5
First step is to solve the multiplication, for this you have to apply the distributive property of multiplications:
[tex]\begin{gathered} f(x)=(-2)\cdot x+(-2)\cdot5 \\ f(x)=-2x-10 \end{gathered}[/tex]Next replace x=5 in the function
[tex]\begin{gathered} f(5)=(-2\cdot5)-10 \\ f(5)=-10-10 \\ f(5)=0 \end{gathered}[/tex]