Question

determinati numarul rational x stiind ca media artimetica ponderata a numerelor 2,4,6si x,cu ponderele9,7,5si respectiv3,este egal cu4,1(6))

Answer 1

(2×9+4×7+6×5+x×3):(9+7+5+3)=4,1(6)

(18+28+30+3x):24=(416-41):90
(18+58+3x):24=375:90 |×6
(76+3x):4=375:15
(76+3x):4=25 |×4
76+3x=100 |-76
3x=24 |:3
x=8