Question

1. Rezolvați prin metoda substituției:

a) $\left \{ {{x+y=5} \atop {x-y=3}} \right.$
b) $\left \{ {{x+y=1999} \atop {x-y=-1999}} \right.$
c) $\left \{ {{-2x+y=0} \atop {1,5x+y=3,5}} \right.$
d) $\left \{ {{ \frac{1}{2}x-0,25y=1 } \atop {-0,5+ \frac{1}{4}y=-1 }} \right.$
e) $\left \{ {{ \sqrt{3x}-2y=1 } \atop {3x-2 \sqrt{3}y= \sqrt{3} }} \right.$

Answer 1

stiu doar la a si b:
a) 2x=8=> x=4=> y=1
b)2x=0=> x=0=> y=1999