Question

Utilize a fórmula de Bháskara

a) x² +2x-15=0

Answer 1

$x^2 + 2x - 15 = 0 \\ \\ \\ x = \dfrac{-b \pm \sqrt{b^2 -4*a*c}}{2*a}$

a=1, b=2, c=−15

Δ=b²−4ac
Δ=(2)2−4*(1)*(−15)
Δ=4+60
Δ=64

$x = \dfrac{-b \pm \sqrt{\triangle}}{2*a}$

$x = \dfrac{-2 \pm \sqrt{64}}{2*1} \\ \\ \\ x = \dfrac{-2 \pm 8}{2} \\ \\ \\ x' = \dfrac{-2 - 8}{2} \\ \\ \\ x' = \dfrac{-10}{2} \\ \\ \\ x' = -5 \\ \\ \\ x'' = \dfrac{-2 + 8}{2} \\ \\ \\ x'' = \dfrac{6}{2} \\ \\ \\ x'' = 3$

S = {-5, 3}