Help with 1 more question! @phi

Question

anonymous · Answer

attachment

phi · Answer

first line
f(x) = 3x+2   x<5

at x=5, will we have an open circle or a solid circle?

phi · Answer

x<5  means  open or solid ?

anonymous · Answer

solid?

phi · Answer

I guess this is not sinking in.   when you say  x<5
that means x is less than 5 (but it can't be *exactly* 5)
we put an open circle at 5 to show that at 5 x is a hole, it isn't really allowed to be 5

anonymous · Answer

ok sorry, i wasn't sure.

phi · Answer

first line
f(x) = 3x+2   x<5

 x<5 means at x=5, will we have an open circle or a solid circle?

anonymous · Answer

open. and that gives me two options. this one

anonymous · Answer

or this one

phi · Answer

not so fast.  Yes, we want an open circle.  but where is the open circle?
use f(x) = 3x+2   x<5
but at x=5
what is f(5) ?

phi · Answer

do you know how to replace x with 5  in   f(x) = 3x+2  
and simplify to get the answer ?

anonymous · Answer

just put 5 at the 3x but replace the x with 5 right?

anonymous · Answer

and simplify

phi · Answer

what do you get ?

anonymous · Answer

f(x)=17

phi · Answer

so the open circle will be at  (5,17)

what choices work ?

anonymous · Answer

only this one. this is the answer, no?

phi · Answer

If that is the only one, then that is the answer.

as a double check, the second line is
f(x) = -3x -2   x≥5
at x=5 will we have an open circle or a solid circle ?

phi · Answer

then check the point   f(5)= -3*5 -2 = -17
or (5,-17) to see if you have the correct circle there.