Question

As raízes da equação x^2-5x+6=0 são

(A) 2 e - 3

(B) -2 e 3.

(C) 2 e 3.

(D) -2 e - 3

Answer 1

$a=1 \ \ \ \ b=-5\ \ \ \  c=6\\\\x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}=\frac{-(-5)\pm\sqrt{(-5)^2-4\cdot1\cdot6}}{2\cdot1}=\frac{5\pm\sqrt{25-24}}{2}=\frac{5\pm\sqrt{1}}{2}=\frac{5\pm1}{2}\\\\x'=\frac{5+1}{2}=\frac{6}{2}=3\\\\\\\\\\x''=\frac{5-1}{2}=\frac{4}{2}=2$

S = {2, 3}