I) 2x² -7x - 15 = 0, a = 2, b = -7 e c = - 15
Δ = b² - 4.a.c
Δ= (-7)² - 4.2.-15
Δ = 49 + 120
Δ = 169
II) X' = - b +√Δ / 2.a
Obs> √169 = 13
x' = [tex] \frac{-(-7)+13}{2.2} [/tex]
x'=[tex] \frac{20}{4} = 5[/tex]
X'' = -b -√Δ/2a
X'' = [tex] \frac{7-13}{2.2} = \frac{-6}{4}= \frac{-3}{2} [/tex]
