Răspuns :
fie x,3x numerele
⇒3x-x=40:4
2x=10
x=10:2
x=5
3x=3x5=15
verificare:15-5=10
40:4=10
10=10
⇒3x-x=40:4
2x=10
x=10:2
x=5
3x=3x5=15
verificare:15-5=10
40:4=10
10=10
a-b = 40:4
a-b = 10
a:b = 3
a = 3*b
3b-b = 10
2b = 10
b = 10:2
b = 5
a = 3*b
a = 3*5
a = 15
proba
15-5 = 10
a-b = 10
a:b = 3
a = 3*b
3b-b = 10
2b = 10
b = 10:2
b = 5
a = 3*b
a = 3*5
a = 15
proba
15-5 = 10