Question

achar a raíz da equação x² - 8x + 7 = 0

Answer 1

x² - 8x + 7 = 0

a= 1
b= -8
c= 7

Δ= b² -4  *a *c
Δ= (-8)² -4 *1*7
Δ= 64 - 28
Δ= 36

-b +- √Δ / 2*a
-(-8) +- √36   /2*1
8 +- 6 / 2*1

x' = $\frac{8+6}{2}$
x' = $\frac{14}{2}$
x' = 7

x" = $\frac{8-6}{2}$
x" = $\frac{2}{2}$
x" = 1

S{ 7 e 1 } 

Answer 2

x² - 8x + 7 = 0
a = 1; b = - 8; c = 7
Δ = b²  -4ac
Δ = (-8)² - 4.1.7
Δ = 64 - 28
Δ = 36

x = - b +/- √Δ   = - (-8) +/- √36
      --------------    --------------------
            2a                   2.1

x =  8 + 6
      ---------  = 14/2 = 7
          2 

x =  8 - 6   = 2/2 = 1
      --------
          2

Resp.: x = 7 ; x = 1