I don’t understand how to get the answer

x = –5 or x = 3

Solution:

Given expression:

⇒ –x – 1 = 4 or –x – 1 = 4

First take –x – 1 = 4.

Add 1 on both side of the equation.

⇒ –x – 1  + 1 = 4 + 1

⇒ –x = 5

Divide by –1 on both side of the equation, we get

⇒ x = –5

Now take –x – 1 = –4.

Add 1 on both side of the equation.

⇒ –x – 1  + 1 = –4 + 1

⇒ –x = –3

Divide by –1 on both side of the equation, we get

⇒ x = 3

x = –5 or x = 3

Hence the two values of x are –5 or 3.