Verified answer

x² - 3x - 10 = 0

x = (3 ± √9 + 40)/2

x = (3 ± √49)/2

x = (3 ± 7)/2

x' = (3 + 7)/2

x' = 10/2

x' = 5

x'' = (3 - 7)/2

x'' = -4/2

x'' = -2

-2 e 5

f(x) => 2x-3x-10=0

......... 2x-3x=0+10

.......... -x=10......x(-1)

........... x=-10

x² - 3x - 10 = 0

x1 = A - B

x2 = A + B

x1 + x2 = 2A = 3

A = 3/2

x1*x2 = A² - B²

-10 = 9/4 - B²

B² = 9/4 + 10 = 49/4

B = 7/2

x1 = A + B = 3/2 + 7/2 = 5

x2 = A - B = 3/2 - 7/2 = -4/2 = -2

pronto