Question

resolva as equações do 2° grau: 7x²+13x-2=0

Answer 1

Note que, $a=7, b=13$ e $c=-2$.

Logo, $x=\dfrac{-13\pm\sqrt{13^2-4\cdot7\cdot(-2)}}{2\cdot7}=\dfrac{-13\pm15}{14}$

$x'=\dfrac{-13+15}{14}=\dfrac{1}{7}$

$x"=\dfrac{-13-15}{14}=-2$

Assim, $\text{S}=\{-2, \frac{1}{7}\}$.

Answer 2

Delta:(13)² - 4(7)(-2)=169 + 56 =225
x'= (-13+ raiz de 225)/14= (-13+15)/14=1/7
x"= (-13- raiz de 225)/14=( -13 - 15)/14= -2