Question

Se stie ca a-b=863,prin impartirea lui a la b obtinem catul 12 si restul 5,iar 5b=3c. Sa se afle 2a+b-c

Answer 1

a-b=863
a:b=12r5 =>a=12b+5
5b=3c
Inlocuim
12b+5-b=863
11b+5=863
11b=863-5
11b=858
b=78
a=12b+5
a=12x78+5=936+5=941
941-78=863
5b=3c=>3c=5b
3c=5x78
3c=390
c=390:3
c=130
2a+b-c=
2x941+78-130=
1882+78-130=
1960-130=1830

Answer 2

a - b = 863
a : b = 12 rest 5 ==>
==> a = 12×b+5 (conform T.I.R)

Inlocuim in prima relatie pe a
12×b+5 - b = 863
11 × b = 863 - 5
11 × b = 858
b = 858 : 11
b = 78

a = 863 + 78 = 941

5×b = 3×c
5×78 = 3×c
390 = 3×c
c = 390 : 3
c = 130

2×a + b - c =
= 2 × 941 + 78 - 130 =
= 1882 + 78 - 130 =
= 1960 - 130 =
= 1 830