Question

X ao quadrado - 13 x + 42

Answer 1

Explicação passo-a-passo:

$\sf x^2-13x+42=0$

$\sf \Delta=(-13)^2-4\cdot1\cdot42$

$\sf \Delta=169-168$

$\sf \Delta=1$

$\sf x=\dfrac{-(-13)\pm\sqrt{1}}{2\cdot1}=\dfrac{13\pm1}{2}$

$\sf x'=\dfrac{13+1}{2}~\Rightarrow~x'=\dfrac{14}{2}~\Rightarrow~\red{x'=7}$

$\sf x"=\dfrac{13-1}{2}~\Rightarrow~x"=\dfrac{12}{2}~\Rightarrow~\red{x"=6}$