Question

Calcullati: x*2 +4x+ 3 ; x'2-2x-3; 9 • x*2 +6x -35 .mersi!

Answer 1

[tex] a) x^{2} +4x+3=0\\ \Delta=b^2-4*a*c=16-12=4\\ x_1=\frac{-b-\sqrt{\Delta}}{2*a}= \frac{-4-2}{2}=\frac{-6}{2}=-3\\ x_2=\frac{-b+\sqrt{\Delta}}{2*a}= \frac{-4+2}{2}= \frac{-2}{2} =-1\\ b) x^{2} -2x-3=0\\ \Delta=b^2-4*a*c=4-4*(-3)*1=4+12=16\\ x_1=\frac{-b-\sqrt{\Delta}}{2*a}=\frac{2-4}{2}= \frac{-2}{2}=-1\\ x_2=\frac{-b+\sqrt{\Delta}}{2*a}=\frac{2+4}{2}=\frac{6}{2}=3 [/tex]
[tex]c) 9 x^{2} +6x-35=0\\\Delta=b^2-4*a*c=36-4*9*(-35)=36+1260=1296\\ x_1=\frac{-b-\sqrt{\Delta}}{2*a}= \frac{-6-36}{2*9}= \frac{42}{18}= \frac{7}{3}\\ x_2=\frac{-b+\sqrt{\Delta}}{2*a}= \frac{-6+36}{2*9}= \frac{30}{18}= \frac{5}{3}[/tex]