Question

3- Resolva as equações do 2º grau, sem utilizar a fórmula resolutiva (0,4)
a) x2 - 49 = 0
b) x2 -5x = 0
c) x2 - 8x + 7 =0
d) x2 - 2x - 3=0

Answer 1

a) x2 - 49 = 0

x × 2 - 49 = 0

2x - 49 = 0

2x = 49

49

x = -----

2

b) x2 -5x = 0

x × 2 - 5x = 0

2x - 5x = 0

-3x = 0

x = 0

c) x2 - 8x + 7 =0

x × 2 - 8x+ 7 = 0

2x - 8x + 7 = 0

-6x + 7 = 0

-6x = -7

7

x = ----

6

d) x2 - 2x - 3=0

x × 2 - 2x - 3 = 0

-3 = 0