Răspuns:
Explicație pas cu pas:
x +3y = a ;
2y -z = b
----------------------
a) x+5y-z = (x+3y) + (2y-z) = a + b
b) x + y + z = (x+3y) - (2y-z) = a - b
c) 2x+8y-z = 2(x+3y) + (2y-z) = 2a + b
d) 3x+7y+z = 3(x+3y) - (2y-z) = 3a - b
e) 2x+3z = 2(x+3y) - 3(2y-z) = 2a - 3b
#copaceibrainly
