Question

ajudeem ? 25x²-5x-2=0

Answer 1

Delta = (-5)² - 4(25)(-2)
           25 - (-200)
           25 + 200
Delta = 225

Para descobrir o x:

-(-5) + $\sqrt{225}$ / 2.25

5 + 15 /50

20/50  = $\frac{2}{5}$

O outro valor de x:

-(-5) - $\sqrt{225}$ /2.25

5 - 15/50

-10/50 = -$\frac{1}{5}$

Solução: { $\frac{2}{5}$ ; -$\frac{1}{5}$}

Answer 2

$25 x^{2} -5x-2=0\\\\ a=25;b=-5;c=-2\\\\\\ \Delta=b^2-4ac\to \Delta=(-5)^2-4*25*(-2)\to \Delta=25+200\to \Delta=225\\\\ \Delta\ \textgreater \ 0\to x' \neq x''\\\\ x= \frac{-b\pm \sqrt{\Delta} }{2a} \to x= \frac{-(-5)\pm \sqrt{225} }{2*25} \to x= \frac{5\pm 15 }{50} \to \\\\\\ x'= \frac{5+15 }{50} \to x'= \frac{20 }{50} \to x'= \frac{2}{5} \\\\\\ x''= \frac{5-15 }{50} \to x''= \frac{-10 }{50} \to x''=- \frac{1}{5} \\\\\\\\ S=\left \{ - \frac{1}{5}; \frac{2}{5}\left \}$