Question

Rezolvati in R ecuatia 7x2la patrat+12x-5=0 ?

Answer 1

28+12x-5=0
23+12x=0
12x=-23
x=(transformi in fractie,simplifici,si dupa imparti daca se poate)

Answer 2

$\displaystyle 7x^2+12x-5=0 \\ a=7,b=12,c=-5 \\ \Delta=b^2-4ac=12^2-4 \cdot 7 \cdot (-5)=144+140=284 \\ x_1= \frac{-12+ \sqrt{284} }{2 \cdot 7} = \frac{-12+2 \sqrt{71} }{14} = \frac{2(-6+ \sqrt{71}) }{14} = \frac{-6+ \sqrt{71} }{7} \\ \\ x_2= \frac{-12- \sqrt{284} }{2 \cdot 7} = \frac{-12-2 \sqrt{71} }{14} = \frac{2(-6- \sqrt{71} )}{14} = \frac{-6- \sqrt{71} }{7}$