Question

resolva as equações a seguir.
a) 18x - 43 = 65
b) 23x - 16 = 14 - 17x
c) 10y - 5 (1 + y) = 3 (2y - 2) - 20
d) x (x+4) + x (x+2) = 2x²+12
e) 4x (x+6) - x² = 5x²

Answer 1

a)
18x - 43 = 65
18x = 65 + 43
18x = 108
x = 6

b)
23x - 16 = 14 - 17x
23x + 17x = 14 + 16
40x = 30
4x = 3
x =  3
      ----
       4

c)
10y - 5 (1 + y) = 3 (2y - 2) - 20
10y - 5 - 5y = 6y - 6 - 20
5y - 5 = 6y - 26
- 5 + 26 = 6y - 5y
21 = y
y = 21

d)
x.(x + 4) + x.(x + 2) = 2x² + 12
x² + 4x + x² + 2x = 2x² + 12
x² + x² + 4x + 2x = 2x² + 12
2x² + 6x = 2x² + 12
2x² - 2x² + 6x = 12
6x = 12
x = 12/6
x = 2

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e)
4x.(x + 6) - x² = 5x²
4x² + 24x - x² = 5x²
3x² + 24x = 5x²
- 5x² + 3x² + 24x = 0
- 2x² + 24x = 0 (-1)
2x² - 24x = 0
x.(2x - 24) = 0
x = 0
2x - 24 = 0
2x = 24
x = 24/2
x = 12

R.: x = 0; x = 12