Question

Resolver em R as equações do primeiro e 2o grau:

a) 5x + 2 = 9x −1

b) 3−3(x − 2) = 2x − (x − 4)

c) x - x/6 = -3

d) 5(z +1) − 2(3z +1) = 4(5 − z)

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e) - x² - x = 0

f) 2x² – 4x + 1 = 0

Answer 1

Boa tarde

a) 5x + 2 = 9x − 1 

9x - 5x = 2 + 1
4x = 3
x = 3/4 

b) 3−3(x − 2) = 2x − (x − 4) 

3 - 3x + 6 = 2x - x + 4
3x + 2x - x = 9 - 4
4x = 5
x = 5/4 

c) x - x/6 = -3

6x/6 - x/6 = -3
5x/6 = -3
5x = -18
x = -18/5 

d) 5(z +1) − 2(3z +1) = 4(5 − z) 

5z + 5 - 6z - 2 = 20 - 4z
-z + 4z = 20 - 3
3z = 17
z = 17/3  

e) - x² - x = 0

x² + x = 0
x*(x + 1) = 0
x1 = 0
x2 = -1

f) 2x² – 4x + 1 = 0 

delta
d² = 16 - 8 = 8
d = 2√2

x1 = (4 + 2√2)/4
x2 = (4 - 2√2)/4