Question

x²-3x-10=0 quero saber x' e x"

Answer 1

DELTA= b2-4ac         = (-3).2-4.1.(-10) = 9+40 49  Raiz de 49=7 

-b+ou-raizdedelta/2a     

+3+ou-7/2

3+7/2 
10/2= 5 = x'

3-7/2 

-4/2 = -2 = x"

Answer 2

x'= [3+√(9 + 40) ]/2 = (3+7)/2 = 5
x''=[3-√(9+40) ] /2 = (3-7)/2 = -4/2 = -2

ou usando o binômio

x² -3/2x + 9/4 - 9/4 -10 = 0
(x-3/2)² = 10 + 9/4
(x - 3/2)² = 49/4
x - 3/2 = 7/2
x' = 3/2 + 7/2 = 10/2 = 5
x'' = 3/2 - 7/2 = - 4/2 = -2