Question

determine os zeros das funções quadraticas

Answer 1

a)

$-x^2+2x+3=0\\ \Delta=2^2-4\cdot (-1)\cdot 3\\ \Delta=16\\\\ x=\dfrac{-2\pm 4}{2\cdot (-1)}\\\\ x'=-1;~x''=3$

b)

$x^2-2x+1=0\\(x-1)^2=0\Rightarrow x-1=0\Rightarrow x=1$