Question

me responda a equação de 2 grau: x2-8x+15=0

Answer 1

$x^2 \ - \ 8x \ + \ 15 \ = \ 0 \\ \\ a \ = 1 \ \ \ \ b \ = - \ 8 \ \ \ \ \ c \ = \ 15 \\ \\ \Delta \ = \ b^2 \ - \ 4ac \\ \\ \Delta \ = \ (- \ 8)^2 \ - \ 4 \ * \ 1 \ * \ 15 \\ \\ \Delta \ = \ 4 \\ \\ x \ = \ \frac{- \ b \ \pm \ \sqrt \ \Delta }{2 \ a}$

$x \ = \ \frac{- \ (- \ 8) \ \pm \ \sqrt \ 4}{2 \ * \ 1} \\ \\ x \ = \frac{8 \ \pm \ 2}{2} \\ \\ x' \ = \ (8 \ + \ 2) \ \div \ 2 \\ \\ x' \ = \ 10 \ \div \ 2 \\ \\ x' \ = \ 5 \\ \\ x'' \ = \ (8 \ - \ 2) \ \div \ 2 \\ \\ x'' \ = \ 6 \ \div \ 2$

$x'' \ = \ 3 \\ \\ Resposta: \ \{5; \ 3 \}$