Finding an angle that's 20 more than four times its supplement

[Imparcticle]

I was doing my geometry homework earlier and came across a problem:

Find m<S if m<S is 20 more than four times its supplement.

What I did:
m<S= x
supplement of m<S: x = (x-180)

how I worked it out:
x=4(x-180) + 20
x=4x-700
700=3x
233.333... = x

My answer for x is obviously wrong because when I try to find m<S, I get 233.33... again:
x=4(2.333...-180) +20
4(53.33...)= 213.333... + 20 = 233.3333...

This evidently does not make any sense at all. The problem said "supplement", and 233.333... is most certainly not an angle measure which agree with the definition of supplement, I believe.

Please help.

 

[StatusX]

180-x .

 

[Imparcticle]

okay. That does not make a difference.

 

[StatusX]

yes .

 

[Imparcticle]

okay. That does not make a difference.

my mistake. It does make a difference.