f(x) = | 2x - 5 | - 9
Find x, so that f(x) = 0
| 2x - 5 | - 9 = 0
| 2x - 5 | = 9
Since we are using absolute value, then 2x -5 can be 9 o -9
The first solution (for 9):
2x - 5 = 9
2x = 9 + 5 = 14
x = 14/2 = 7
x = 7
The second solution (for -9):
2x - 5 = -9
2x = -9 + 5 = -4
x = -4/2
x = -2
So, we have to values for x that make f(x) = 0
x = 7 and x = -2