C= raspunsuri corecte
G= raspunsuri gresite
C+G=20
10C-2G=176
Rezolvam exercitiul sub forma de sistem.
{C+G=20/*2
{10C-2G=176
⇔
{2C+2G=40
{10C-2G=176
-----------------(adunam)
12C / =216
C=18 raspunsuri corecte
C+G=20
18+G=20
G=20-18
G=2 raspunsuri gresite