Question

qual a resposta de 7x² - 35x = 0 ?

Answer 1

7x^2 - 35x = 0
7x(x - 5) = 0
7x = 0
x = 0/7
x = 0

e

x - 5 = 0
x = 5

S = { 0, 5 }

Answer 2

7x² - 35x = 0
a = 7                b = - 35              c = 0
∆ = b² - 4 . a . c 
∆ = (- 35)² - 4 * 7 * 0
∆ = 1.225 - 0
∆ = 1.225
x = - b + √∆ 
     --------------
         2a
x = - (- 35) + √1.225
     -----------------------------
              2 * 7
x' = 35 + 35
      ------------
          14
x' = 35 + 35 
          14
x' = 70 ÷ 14
x' = 5
x" = 35 - 35
x" 0

Resposta: {5, 0}