Question

De la exercitiul 4 doar ce e incercuit(a si b).

Answer 1

a)
[tex]x^2-2x-1=0\\ a=1\\ b=-2\\ c=-1\\ \Delta=b^2-4ac=4+4=8\\ x_{1,2}= \frac{-b\pm \sqrt{\Delta} }{2a}= \frac{2\pm \sqrt{8} }{2}=1\pm \sqrt{2} [/tex]

b)
[tex]-2x^2+x+3=0\\ a=-2\\ b=1\\ c=3\\ \Delta= 1+24=25\\ x_{1,2}= \frac{-1\pm \sqrt{25} }{-4}= \frac{-1\pm5}{-4} \\ x_1=1,5\\ x_2=-1[/tex]