Question

seja a função y=x2-4x-5

Answer 1

$y=x^2-4x-5 \\ \\ x^2-4x-5 = 0 \\ \\ \Delta=b^2-4ac \\ \Delta=(-4)^2-4.1.(-5) \\ \Delta=16+20 \\ \Delta=36 \\ \\ x= \frac{-b \frac{+}{-} \sqrt{\Delta} }{2.a} \\ \\ x= \frac{-(-4) \frac{+}{-} \sqrt{36} }{2.1} \\ \\ x= \frac{4 \frac{+}{-} 6}{2} \\ \\ x_{l}= \frac{4+6}{2} = 5 \\ \\ x_{ll}= \frac{4-6}{2} = -1$

O zero da função e 5 e -1