00:01
You have the piecewise function f of x is equal to 5x squared minus 3x plus 4, 4x greater than or equal to 0, and x plus 6 over x minus 7 when x is less than 0.
00:22
Part a, f at 0, when you're doing f at 0, you have to use where 0 is defined, so that is in your first equation.
00:33
So plugging in 0, 5 times 0 squared is 0, minus 3 times 0 plus 4 is 4.
00:42
Part b, f of 5, that is going with this first part as well.
00:52
So it's 5 times 5 squared minus 3 times 5 plus 4.
01:00
5 cubed, so 5 times 5 squared is 5 cubed.
01:06
5 cubed.
01:12
125 minus 15 plus 4 is 114.
01:21
Part c, f at negative 7.
01:25
If you're at negative 7, that is less than 0, so you're in the second part.
01:30
So this is negative 7 plus 6 over negative 7 minus 7.
01:36
Negative 7 minus 7 is negative 14 for your denominator and negative 7 plus 6 is negative 1 so this is 114th for part d you have root 2 minus root 3 it's in your best interest to check and see if that is greater than or less than 0 so root 2 minus root 3 is a negative number so it is going here so f of root 2 minus root 3 is root 2 minus root 3 plus 6 over root 2 minus root 3 minus 7.
02:34
If you're asked to rationalize that denominator, you would be multiplying by a conjugate, it, but i don't see that in the directions here...