Question

Soluția naturală a ecustiei? 2x(la a 2 ) -5x-3=0

Answer 1

      
$2 x^{2} -5x-3=0 \\ \\ x_{12}= \frac{-b \pm \sqrt{ b^{2}-4ac}}{2a}= \frac{5 \pm \sqrt{ 25+24}}{4}= \frac{5 \pm \sqrt{ 49}}{4}=\frac{5 \pm 7}{4} \\ \\ x_1 =\frac{5 + 7}{4} =\frac{12}{4}=\boxed{3} \\ \\ x_2 =\frac{5 - 7}{4} =\frac{-2}{4}=\boxed{ \frac{-1}{2} } \\ \\ Solutia\;\; x_2 \;\; va\;\;fi\;\; eliminata\;\; deoarece: \;\; x_2= \frac{-1}{2} \notin N$