Question

3mingi si 2 masinute costa 65 lei ,iar 4mingi si o masinuta costa 70 lei.Aflati cat costa o minge si cat costa o masinuta

Answer 1

3x+2y=65, x=minge, y=masinuta
4x+y=70, y=70-4x si se inlocuieste in prima ecuatie

3x+2 (70-4x)=65
3x+140-8x=65
8x-3x=140-65
5x=75
x=75/5=15

stim ca y=70-4x=70-4*15=70-60=10

x=15, y=10