Question

exercițiul 19 va rog frumos

Answer 1

x+5y+z=x+3y+2y+z
dar x+3y=2y+z=14,
14+14=28
b)3x+15y+3z=3 (x+5y+z)=3×28=84
c)5x+11y-2z=5x+15y-4y-2z=5 (x+3y)-2 (2y+z)=
5×14-2×14=60-28=32
d)5x+19y+2z=5x+15y+4y+2z=5 (x+3y)+2 (2y+z)=
5×14+2×14=60+28=88

Answer 2

x+3y=14
y+z=14  

a)
x+5y+z =(x+3y)+(2y+z)=14+14=28

b) 
3x+15y+3z=3(x+5y+z)=3×28=84

c)
5x+11y-2z=5x+15y-4y-2z=5(x+3y)-2(2y+z)=3*14-2*14=14

d)
5x+19y+2z=5x+15y+4y+2z=5(x+3y)+2(2y+z)=5*14+2*14=7*14=98