Răspuns:
Explicație pas cu pas:
a) Notam |x-1| =u, |y| = v
u +2v = 9, u = 9-2v
2u -3v = 4
2(9-2v) -3v = 4
18 -4v -3v =4
-7v = 4-18 = -14
v = 2, u = 9-2*2 = 5
|x-1| = 5
x-1 = +- 5, x =6 si x = -4
|y| = 2, y = -2 si y = 2
b) |x-1| = y-5, inlocuim in prima ec.:
y-5 + |y-5| = 1
|y-5| = y-5 sau 5-y
y-5 + y-5 = 1
2y = 1+10, y = 11/2
y-5 +5-y = 1, imposibil
|x-1| = y-5 = 11/2 -5 = 1/2
x-1 = +- 1/2
x = 1+1/2 = 3/2 si x = 1-1/2 = 1/2
