Răspuns:
a) x=2
y=(-1)
b)y=5
x=0
c)∅
3
a) 2x-3y+5=0 2x-3y+5=0 2x-3(-3-13)+5=0
→ →
3x+y+13=0 y= -3x-13 y=-3x-13
x=-4 x=-4
→ →
y= -3(-4)-13 y=-1.
4.
a)
2(x+y+1)-3(2x-y-3)=12 2x+2y+2-6x+3y+9=12...
→
4(2x-y-1)+3(3-x-y)=3 8x-4y-4+9-3x-3y=3.....
.........→ x=1
...... y=1
b)√2× x+√5×y=7→√2× x+√5×y=7→√2×(√10y/5)+√5×y=7→y=√5
√5×x-√2×y=0→ √10y/5 → √10×(√5)/5→x=√2.