Question

daca x supra 2 = y supra 3 = z supra 5 si 3x+ 2x-z=21 atunci aflati nr. x,y,z

Answer 1

$\frac{x}{2} = \frac{y}{3} = \frac{z}{5} =k~(constanta~de~proportionalitate) \\ \\ x=2k;~y=3k;~z=5k \\ \\ 3x+2y-z=21 \\ \\ 3*2k+2*3k-5k=21 \\ \\ 6k+6k-5k=21 \\ \\ 7k=21 \\ \\ k=3 \\ \\ x=2*3 \\ x=6 \\ \\ y=3*3 \\ y=9 \\ \\ z=5*3 \\ z=15$