Question

resolva a equação do segundo grau - 2x ao quadrado + 13x - 15 = 0

Answer 1

Vamos lá!

$- 2x {}^{2} + 13x - 15 = 0$
∆=
$13 {}^{2} - 4 \times ( - 2) \times ( - 15)$
169 + 8 × (-15)
169 - 120
∆ = 49

X1 = -13/ 2+ 7 /2 = - 6/-4 = -3/2

X2 = -13/2 -7/2 = -20/-4 = 5

Answer 2

- 2x² + 13x - 15 = 0

a = -2
b = 13
c = -15

Δ = b² - 4ac

Δ = 13² - 4(-2)(15)
Δ = 169 + 8(15)
Δ = 169 + 120
Δ = 49

x = -b +- √Δ / 2a

x = -13 + - √49/ 2(-2)
x = -13 + - 7/ -4

x₁ = -13 - 7 / -4  ⇒ -20/ -4 = 5
x₂ = -13 + 7 / -4 ⇒ -6/ -4 = 3/2

S{ 3/2; 5 }