Răspuns :
=> (rezulta) 28×4=112 (suma)
a=b+28=>
=> b+b+28=112
=> 2×b=112-28
=> 2×b= 84
=> b=84:2
=> b=42
a=b+28=>
=> b+b+28=112
=> 2×b=112-28
=> 2×b= 84
=> b=84:2
=> b=42
suma=28x4
suma=112
a /----------------/-28-/
b /----------------/
112-28=84
84:2=42
a=42+28
a=70
b=42
70-42=28
70+42=112
suma=112
a /----------------/-28-/
b /----------------/
112-28=84
84:2=42
a=42+28
a=70
b=42
70-42=28
70+42=112