Metoda inlocuirii !
y = 3x - 5 ;
4x - 5( 3x - 5 ) = 8 <=> 4x - 15x + 25 = 8 <=> - 11x = - 17 <=> x = 17 / 11 ;
y = 3 × ( 17 / 11 ) - 5 <=> y = 51 / 11 - 5 <=> y = 51 / 11 - 55 / 11 <=>
y = - 4 / 11 ;
Proba :
3 ×( 17 / 11 ) + 1 =51 / 11 + 1 = 62 / 11 ;
- 4 / 11 + 6 = - 4 / 11 + 66 / 11 = 62 / 11 ;
4 × ( 17 / 11 ) - 5 × ( - 4 / 11 ) = 68 / 11 + 20 / 11 =88 / 11 = 8 ;
S = {( 17 / 11 ; - 4 / 11 )}
Bafta !
