Question

resolva as equaçoes a) 2x²--32=O ? b) 3x²+10=22? c)x²--164=0? d)2x²+18=0? e)3(x²--9)=0? f) x²--40=60? g) 5x²+4=49 ?

Answer 1

a) 2x² - 32 = 0
2x² = 32
x² = 32/2
x² = 16
x = +/- √16

x1 = 4            
x2 = -4
_________________________
b) 3x² + 10 = 22
3x² = 22 - 10
3x² = 12
x² = 12/3
x² = 4
x = +/- √4

x1 = 2            
x2 = -2
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c) x² - 164 = 0
x² = 164
x = +/- √164

Decompondo 164:
164        2
82          2
41          41
1

x = +/- √2² . 41
x = +/- 2√41

x1 = 2√41
x2 = -2√41
____________________________
d) 2x² + 18 = 0
2x² = - 18
x² = -18/2
x² = -9
x = +/- √-9
x = +/- √9 . √-1
x = +/- 3i

x1 = 3i
x2 = -3i
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e) 3(x ² - 9) = 0
3x² - 27 = 0
3x² = 27
x² = 27/3
x²= 9
x = +/- √9

x1 = 3
x2 = -3
__________________________
f) x² - 40 = 60
x² = 60 + 40
x² = 100
x = +/- √100

x1 = 10
x2 = -10
______________________________
g) 5x² + 4 = 49
5x² = 49 - 4
5x² = 45
x²= 45/5
x² = 9
x = +/- √9

x1 = 3
x2 = -3

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