Question

Se stie ca 3 lalele si 5 crizanteme costa 34 de lei,iar 9 lalele si 4 crizanteme costa 47 de lei .Calculati cat costa o lalea si cat costa o crizantema.

Answer 1

l - lalele
c - crizanteme

I. 3l + 5c = 34 
II. 9l + 4c = 47

I. 3l + 5c = 34 => 3l = 34-5c
II. 3*3l + 4c = 47 => 3(34-5c)+4c=47 => 102-11c=47 => -11c = 47-102 =>
-11c=-55 /(-1) = 11c=55=> c = 5 lei

Deci:
I. 3l + 5c = 34 => 3l + 25 = 34 =>
3l = 34-25 => 3l = 9 => l = 3 lei

Verificare:
3l + 5l = 34, astfel => 3*3 + 5*5 = 34 => 9+25=34 A
9l + 4c = 47, astfel => 9*3 + 4*c = 47 => 27+20=47 A