7. Rezolvați în R ecuațiile: a) x²-3x+2=0; d) x²-7x+12=0; g) x²+11=4x;​

Răspuns:

a) delta= b²-4ac

delta= 9-4×1×2

delta=1

x1=-b-rad delta/2a= 3-1/2=2/2=1

x2=-b+rad delta/2a=3+1/2=4/2=2

b)delta=b²-4ac

delta=49-4×1×12

delta=49-48= 1

x1= -b-rad delta/2a= 7-1/2=3

x2= -b+rad delta/2a= 7+1/2= 4

c)delta=b²-4ac

delta= 16-4×1×11

delta=16-44

delta=-28

x1= -b-rad delta/2a=> -4-rad 28/2

x2= -b+rad delta/2a=> -4+ rad 28/2

=> x>0 oricare ar fi x€R.