Question

(x+2)(x-3)=0

me ajudem a resolver!

Answer 1

$(x+2)(x-3)=0 \\ x^2-x-6=0$
A soma das raízes é igual a -1 e o produto igual a -6, logo S={-2,3}

Answer 2

Aplicaremos a distributiva

(x+2).(x-3)=0
x² - 3x + 2x - 6 = 0
x² - x - 6 = 0

a = 1
b = -1
c = -6

Δ = b² -4 . a .c 
Δ = (-1)² -4 . 1 . (-6)
Δ = 1 -4 . (-6)
Δ = 1 + 24
Δ = 25

$\mathtt{\dfrac{-b +- \sqrt\Delta}{2~.~a}~~=~~\dfrac{- (-1) +-\sqrt{5}}{2~.~1}~~=~~\dfrac{1 + - ~5}{2}} \\ \\ \\ \mathtt{x' = \dfrac{1 + 5}{2}~~=~~\dfrac{6}{2}~~=~~ \boxed{3}} \\ \\ \\ \mathtt{x'' =\dfrac{1 - 5}{2}~~=~~-\dfrac{4}{2}~~=~~\boxed{-2 }}$

Resposta:  S{ -2 e 3}