Question

x2+8x+15=0
quem são as raizes?

Answer 1

As raízes são os possíveis valores de "x". Para descobrir, basta resolver a equação do segundo grau com Bhaskara:

$x^{2}+8x+15 = 0 \\\\ \Delta = b^{2}-4 \cdot a \cdot c \\\\ \Delta = (8)^{2}-4 \cdot (1) \cdot (15) \\\\ \Delta = 64-60 \\\\ \Delta = 4 \\\\\\ x= \frac{-b \pm \sqrt{\Delta}}{2a} \\\\ x= \frac{-8 \pm \sqrt{4}}{2 \cdot 1} \\\\ x = \frac{-8 \pm 2}{2} \\\\\\ x'= \frac{-8 + 2}{2} = -\frac{6}{2} = \boxed{-3} \\\\ x'' = \frac{-8 - 2}{2} = -\frac{10}{2} = \boxed{-5} \\\\\\ \boxed{\boxed{S = \{-5,-3\}}}$



As raizes são -5 e -3.

Answer 2

X2+8x+15=0

Δ = 8² - 4.1.15 ==> 64 - 60 ==> 4

x = - 8 +/- √4 ==> x= - 8+/-2
           2.1                     2

x1 = - 8 + 2 ==> x1 = - 3
           2

x = - 8 - 2 ==> x1 = - 5
         2