Question

Va rog frumos pls ajutati-ma! Aflati a,b,c daca sunt a supra 3 = b supra 7 = c supra 8 si 2a + 5b -4c=108.

Answer 1

a/3=b/7=c/8
2a+5b-4c=108
din primele 2 egalitati de fractii gasim :
7a=3b , produsul mezilor egal cu produsul extremelor=> a=3b/7
din ultimele doua egalitati de fractii avem:
b/7=c/8=> c×7=b×8=>c=8b/7
inlocuim in ultima relatie si avem:
2×3b/7+5b-4×8b/7=108
6b/7+5b-32b/7=108
aducem ka acelasi numitor
6b+5×7b-32b=108×7
6b+35b-32b=108×7
9b=108×7=>b=108×7/9= 12×7=84
a=3b/7=3×84/7=3×12=36
c=8b/7=8×84/7=8×12=96
proba
2×36+5×84-4×86=72+420-384=108