00:01
Okay, so you have a function that's defined by two equations.
00:05
We call these piecewise function, so i'm going to write it like that.
00:10
If you're not used to this notation, that's okay.
00:14
So it says 5x plus 8 if x is less than 0, and 9x plus 7 if x is greater than or equal to 0.
00:29
So part a, we want f of negative 9.
00:36
Negative 9 is less than 0, so we're going to use the first equation.
00:41
So that's 5 times negative 9 plus 8.
00:46
5 times negative 9 is negative 45, negative 45 times 8, sorry, plus 8 is negative 37.
01:04
Part b, f of 0.
01:08
So notice if it's going to be equal to zero.
01:13
We need to use our second equation...