Why (x-5)+(-2x+1) = x-4-(2*x) ?

juliagat:

Can you give me a short explanation why (x-5)+(-2x+1) = x-4-(2*x) ? Thank you.

left side:
(x-5)+(-2x+1)
x-5+-2x+1
x-2x-5+1
x-2x-5+1
-1x-4
-x-4

right side:
x-4-(2*x)
x-4-2*x
x-2*x-4
-1x-4
-x-4