Question

Exercițiul 9! Va rog îmi trebuie urgent pentru tema! Dau coroana

Answer 1

x/3=y/4=z/5=k
x/3=k⇒x=3k
y/4=k⇒y=4k
z/5=k⇒z=5k
cunoastem valori pentru:x=3k,y=4k si z=5k , vom inlocui in expresii  si aflam pe x,y,z

a)x+y+z=84
3k+4k+5k=84
12k=84
k=7
x=21:y=28si z=35

b)x+2y+3z=52
3k+8k+15k=52
26k=52
k=2
x=6:y=8 si z=10

c)3x+4y+5z=50
9k+16k+25k=50
50k=50
k=1
x=3:y=4 si z=5

d)x²+y²+z²=200
9k²+16k²+25k²=200
50k²=200
k²=4
k=2
x=6:y=8 si z=10

e)1/x+1/y+1/z=47/80
1/3k+1/4k+1/5k=47/80
47/60k=47/80
47·80=60k·47
k=80/60=8/6=4/3
x=4:y=16/3  si z=20/3