Answer:
[tex]f(x)[/tex] is equal to 15 when [tex]x=-5[/tex]
Step-by-step explanation:
Given a function [tex]f(x)[/tex] this means that the function ''f'' depends on the variable ''x'', If you want to obtain the value of [tex]f(x)[/tex] when [tex]x=a[/tex],being ''a'' a possible value of x (this means ''a'' is in the domain of [tex]f(x)[/tex]) you only need to replace [tex]x=a[/tex] in the [tex]f(x)[/tex] equation
If [tex]x=-5[/tex] ⇒
[tex]f(x)=5x+40\\f(-5)=5.(-5)+40=-25+40=15[/tex]
[tex]f(-5)=15[/tex] this means that when [tex]x=-5[/tex] the function value is [tex]15[/tex]
