Question

4 lalele si 3 trandafiri costa 36 lei.
5 lalele si 6 trandafiri costa 50 lei.
Atunci : 1 lalea=?
1 trandafir=?

Answer 1

Notam x - pretul unei lalele
            y - pretul unui trandafir
[tex] \left \{ {{4x+3y} =36\atop {5x+6y}=50} \right. \left \{ {4x=36-3y} \atop {5(36-3y)+6y=50}} \right. \left \{ {{4x=36-3y} \atop {180-15y+6y=50}} \right. \left \{ {{4x=36-3y} \atop {-9y=50-180}} \right. \left \{ {{4x=36-3y} \atop {-9y=-130}} \right. [/tex] $\left \{ {{4x=36-3y} \atop {9y=130}} \right. \left \{ {{4x=36-3y} \atop {y=14}} \right. \left \{ {{4x=36-3*14} \atop {y=14}} \right. \left \{ {{4x=} \atop {x}} \right.$