Question

sa se determine nr real a stiind ca dreptele 2x-y+3=0 si ax +2y+5=0 sunt paralele.

Answer 1

d1:2x-y+3=0 -y=-2x-3 Md1=-2 d2:ax+2y+5=0 2y=-ax-5 y=-ax-5/2 y=-ax/2-5/2 Md2=-a/2 Md1 || Md2→Md1=Md2→-2=-a/2→-4=-a|(-1)→a=4