Odpowiedź :
[tex]20+x=40\\x=40-20\\x=20\\\\60+x=100\\x=100-60\\x=40\\\\-30+x=10\\x=10+30\\x=40\\\\-100+x=700\\x=700+100\\x=800[/tex]
a)
20 + x = 40
x = 40 - 20
x = 20
b)
60 + x = 100
x = 100 - 60
x = 40
c)
-30 + x = 10
x = 10 + 30
x = 40
d)
-100 + x = 700
x = 700 + 100
x = 800