Question

Fie x,y si z numere reale astfel incat x+3y=11 si 2y+z=5. Determinati:
a) x+y-z;

b)x+5y+z;

c)2x+6y+5;

d)3x+7y-z;

e) x-y-2z;

f) 7-4y-2z.

Repede va rog!!!Dau funda si ofer 29 de puncte!!

Answer 1

a) x+y-z = x+3y-2y-z = x+3y-(2y+z) = 11-5 =6
b) x+5y+z = x+3y+2y+z = 11+5 = 16
c) 2x+6y+5 = 2(x+3y)+5 = 2*11+5 = 27
d) 3x+7y-z = 3x+9y-2y-z = 3(x+3y)-(2y+z) = 3*11-5 = 28
e) x-y-2z = x+3y-4y-2z = x+3y-2(2y+z) = 11-2*5 = 1
f) 7-4y-2z = 7-2(2y+z) = 7-2*5 = -3