Question

{x,y,z} direct proportionale {2,5,6} 2x +3y -z =130
x,y,z?

Answer 1

x=2k y=5k z=6k   4k+15k-6k=130    13k=130 k=10 x=20 y=60 z=60

Answer 2

x/2=y/5=z/6=k
x=2k,  y=5k, z=6k
2x+3y-z=130

2×2k+3×5k-6k=130
4k+15k-6k=130
13k=130
k=130:13
k=10
deci
x=2k,  y=5k, z=6k
x=20, y=50 si z=60