Question

4) Resolva as equações do 2º grau:
a) 4x2 - 36 = 0
b) 7x2 - 21 = 0
c) x2 + 9x = 0
d) x2 - 4x = 0​

Answer 1

Resposta:

a-) 4x × 2 -36 = 0

4x = 0 +36 -2

4x = 34

x = 34÷4

x = 8,5

b-) 7x × 2 -21 = 0

7x = 0 +21 -2

7x = 19

x = 19÷7

x = 2,8

c-) x × 2 + 9x = 0

x + 9x = 0 -2

8x = -2

x = -2 ÷ 8

x = -0,25

d-) x × 2 -4x = 0

x -4x = 0 -2

-3x = -2

x = -2 ÷ -3

x = 1,5