Question

como resolver essa equação -2x²-5x+7=0

Answer 1

d = (-5)^2 - 4*(-2)*7
d = 25 + 56
d = 81

x' = 5 + 9 / 2
x' = 14/2 = 7

x" = 5-9 / 2
x" = -4/2
x"=2

Answer 2

- 2x^2 - 5x + 7 = 0 .(- 1)
2x^2 + 5x - 7 = 0

(Fórmula de Bháskara)

a = 2
b = 5
c = - 7

Delta = b^2 - 4.a.c
Delta = 5^2 - 4.2.(- 7)
Delta = 25 - 8.(- 7)
Delta = 25 + 56
Delta = 81

x = - b +- VDelta/2.a
x = - 5 +- V81/2.2
x = - 5 +- 9/4

x' = - 5 - 9/4
x' = - 14/4 (÷ 2) => Simplificando
x' = - 7/2

x" = - 5 + 9/4
x" = 4/4
x" = 1