dketahui sudut - sudut berikut nilai x+y-z

2x + 40= 130
2x= 130-40
x = 90:2
= 45
y+10= 40
y= 40-10
y= 30
3z + 20 = 80
3z = 80-20
z= 60:3
= 20
x + y - z = 45+30-20
=55