How do I do this problems ? periods?

Question

I Ix - 3I - 9 I = 2
I don't know how to do this problems like this with periods I don't know how to say to this I in english Is period good . And also show me how to do this problem.

Answer 1

At first Ix-3I-9=+-2
lets start with+2
Ix-3I=11Now if x>3
x-3=11 and x=14 (solution)
if x<3
3-x=11 so x= -8 (solution)
now
Ix-3I-9=-2
Ix-3I=7
if x>3 x-3=7 so x=10(solution)
if x<3
3-x=7 so x=-4 (solution)
so we have 4 solutions
the sign I I means absolute value

Answer 2

I Ix - 3I - 9 I = 2
| x - 3 - 9| = 2
|x - 12| = 2
x - 12 = 2
x = 2 + 12
x = 14

Answer 3

(|x-3|-9)^2 = 4